High performance digital loop diagnostic technology

ABSTRACT

Methods and associated hub arrangements are described for use in diagnosis and recovery in high performance digital loops such as, for example, those seen in Fibre Channel systems. In one system having a hub configured for interconnection of a plurality of stations as part of a digital system such that digital data flows between the stations based on operational status of the system, an arrangement forms part of the hub which arrangement is connectable at points within the hub and between at least two different pairs of the stations for monitoring certain characteristics of the data in a way which provides for non-invasive identification of one or more conditions related to the operational status of the system.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to the field of digitalloop technology utilizing a hub structure and, more particularly, to thefield of diagnosis and recovery using a hub in high performance digitalloops such as, for example, those hubs seen in Fibre Channel systems.

[0002] The value of the digital loop in high performance systems such asFibre Channel is without question. Moreover, the use of such a loop hasproven to be enhanced through the use of a hub which serves as a centralconnection point for the loop. In such a configuration, the loop is saidto be in the form of a “star”. Initial development of hubs saw what maybe referred to as an unmanaged or “dumb” hub. As these terms indicate,such hubs served much in the manner of a patch panel, devoid of anymonitoring capability as to the data passing through the hub.

[0003] Still considering the hub technology of the prior art, attentionis now directed to FIG. 1 which illustrates a more recent digital systemgenerally indicated by the reference numeral 10. System 10 includes aFibre Channel hub 12 serving to interconnect a loop 14 including aplurality of stations S1-S4. System 10 further includes a local areanetwork (LAN) 16 having independent connections 17a and 17b withstations S1 and S2, respectively. LAN 16 further includes a station S5as well as a work station (WS) 18. Unlike the earlier generation of hubsdescribed above, hub 12 includes limited diagnostic capabilities. Thesecapabilities have generally been limited to high level observation ofthe data traveling around the loop. More specifically, these prior artdiagnostic capabilities may indicate that certain packets of data arecorrupted in addition to indicating the point of origination of thecorrupted data. At first blush, this may seem to be extremely usefulinformation for purposes of diagnosis. One must remember, however, thatthe corrupted data may have traveled through a substantial number ofstations between it's point of origin and it's destination. For example,data originating from S2 and destined for S1 on the loop mustintermediately pass through stations S3 and S4. Therefore, it ispossible for the data to have been corrupted at any point along thispath. An unsuspecting system administrator who immediately assumes thatS2 is responsible for the corrupted data can waste enormous effort inattempting to diagnose a problem which may occur anywhere along the loopbetween S2 and SI.

[0004] Still referring to FIG. 1, in attempting to perform a detaileddiagnosis, a technician may utilize a logic or protocol analyzer 20. S2and hub 12 are originally connected using cable 22. The analyzer may beconnected by disconnecting the original cable 22 at one end and thenreconnecting the disconnected end to the analyzer such that originalcable 22 is represented as a dashed line indicated by the referencenumber 22a and an additional cable 24 is used to connect the analyzerwith S2. Assuming the problem is not being caused by S2, the technicianhas little hope of resolving the problem using the analyzer as depicted.Thus, the use of an analyzer in such a scenario is disadvantageous.Moreover, as another disadvantage, it is important to note that the useof the analyzer is intrusive. That is, connection of the analyzer itselfmodifies the structure of the loop. This fact can cause severecomplications in some cases. For example, if the problem is being causedby a loose connector (not shown) at S3, connection of the analyzer maymake the problem disappear if the output signal of the analyzer isgreater than the output signal of S2 whereby to overcome attenuationbeing caused by the loose connector at S3. In this scenario, areasonable technician may assume that the problem has somehow correcteditself, since the analyzer will indicate that there are no errors.Unfortunately, however, as soon as the original connections arerestored, the masked problem will return. The technician is then likelyto remain suspicious of S2, replacing it and its associated connectionsand is also likely to suspect fiber 22. As can be appreciated, thisdisadvantageous hit or miss technique is likely to be a long process.Moreover, each time a connection is disturbed to insert the analyzer,the loop is taken out of service. The process can also be expensive justdue to replacement of any number of perfectly good, but suspectcomponents.

[0005] Continuing to consider the use of an analyzer, it should also beappreciated that analyzer diagnosis is further complicated by the factthat the analyzer is generally configured to monitor only one or twopoints. This is an important consideration since the loop, unlike LAN16, is not a broadcast medium. That is, the data present betweendifferent pairs of stations on loop 14 is itself different since thestations themselves insert and remove data from the loop. Just throughthe use of an analyzer, it is very difficult to gain a complete“picture” of what is going on in the loop which may, in fact, representthe only way in which a particular problem may be understood. Not onlyis the analyzer ineffective in many cases, it is also typicallyexpensive. It is not uncommon for a Fibre Channel analyzer to cost$45,000.

[0006] The present invention provides a highly advantageous arrangementand associated method which resolves the foregoing disadvantages anddifficulties while providing still further advantages, as will be seenhereinafter.

SUMMARY OF THE INVENTION

[0007] As will be described in more detail hereinafter, there aredisclosed herein methods and associated hub arrangements for use indiagnosis and recovery in high performance digital loops such as, forexample, those seen in Fibre Channel systems. Accordingly, within a hubconfigured for interconnection of a plurality of stations as part of adigital system such that digital data flows between the stations basedon operational status of the system, an arrangement forms part of thehub which arrangement is connectable at points within the hub andbetween at least two different pairs of the stations for monitoringcertain characteristics of the data in a way which provides fornon-invasive identification of one or more conditions related to theoperational status of the system.

[0008] In one aspect of the invention, recovery from a condition whichis adverse to the operation of the system is initiated based onidentification of the adverse condition.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention may be understood by reference to thefollowing detailed description taken in conjunction with the drawingsbriefly described below.

[0010]FIG. 1 is a block diagram illustrating a digital system includinga prior art Fibre Channel hub and a prior art analyzer used with thehub.

[0011]FIG. 2 is a diagrammatic block diagram of a digital system in theform of a loop which is defined using a hub manufactured in accordancewith the present invention in an implementation which utilizes a fixeddiagnostic unit and a roving diagnostic unit.

[0012]FIG. 3 is a block diagram illustrating the system of FIG. 2 shownhere to illustrate further details of construction of the hub inaccordance with the present invention.

[0013]FIG. 4 is a schematic in block diagram form shown here toillustrate one implementation of an integrated port control circuitmanufactured in accordance with the present invention and used in thesystem shown in FIGS. 2 and 3.

[0014]FIG. 5 is a partial cut-away view of the system of FIG. 3 in blockdiagram form shown here to illustrate monitoring in accordance with thepresent invention using the roving diagnostics unit.

[0015]FIG. 6 is another partial cut-away view of the system of FIG. 3 inblock diagram form shown here to illustrate other aspects of monitoringin accordance with the present invention using the roving diagnosticsunit.

[0016]FIG. 7 is still another partial cut-away view of the system ofFIG. 3 in block diagram form shown here to illustrate an initializationprocedure performed in accordance with the present invention.

[0017]FIG. 8 is a partial cut-away view in block diagram form of thesystem shown in FIG. 3 shown here for purposes of illustrating anotherinitialization procedure performed in accordance with the presentinvention.

[0018]FIG. 9 is a diagrammatic illustration of the possible physicalappearance of a port connection panel of a hub manufactured inaccordance with the present invention shown here to illustrate featuresincorporated into the hub.

[0019]FIG. 10 is a diagrammatic illustration of a display screen showinga site management view in accordance with the present invention.

[0020]FIG. 11 is a diagrammatic illustration of display screen showing astack view in accordance with the present invention which is obtained byselection in the site management view of FIG. 10.

[0021]FIG. 12 is a diagrammatic illustration of display screen showing ahub view associated with one of the hubs shown in FIG. 10.

[0022]FIG. 13 is a diagrammatic illustration of display screen showing aport detail screen that appears through selection of one of the ports inFIG. 12 and which provides information and control facilities for theselected port.

[0023]FIG. 14 is a diagrammatic illustration of display screen showing ahub sweep view in accordance with the present invention that appearsthrough selection of a logo in FIG. 12 and which provides detailedinformation for each port in a single view.

[0024]FIG. 15 is a diagrammatic illustration of display screen showing aper port diagnostic screen in accordance with the present invention.

[0025]FIG. 16 is a partial cut-away view in block diagram form of thesystem shown in FIG. 3 shown here for purposes of illustrating full pathend-to-end verification performed in accordance with the presentinvention on a lobe attached to the hub.

[0026]FIG. 17 is a diagrammatic illustration in block diagram form of aFibre Channel system including a hub manufactured in accordance with thepresent invention for use in describing a number of highly advantageousfeatures of the present invention including features relating todiagnostics for evaluation of remote, unmanaged devices.

[0027]FIG. 18 is a diagrammatic illustration of a data managementarrangement implemented on a host system including a method used in thehost system for collecting data, evaluating the data and providingindications based thereon in accordance with the present invention.

[0028]FIG. 19 is a diagrammatic illustration in block diagram form of aFibre Channel system including two hubs manufactured in accordance withthe present invention for use in describing topology mapping performedin accordance with the present invention.

[0029]FIG. 20 is a diagrammatic illustration in block diagram form of aFibre Channel system including two hubs at least one of which ismanufactured in accordance with the present invention for use indescribing hot cascading performed in accordance with the presentinvention.

[0030]FIG. 21 is a flow diagram illustrating a first hot cascadingmethod performed in accordance with the present invention on the systemof FIG. 20.

[0031]FIG. 22 is a flow diagram illustrating a second hot cascadingmethod performed in accordance with the present invention on the systemof FIG. 20.

[0032]FIG. 23 is a diagrammatic illustration of an integrated portcontrol circuit manufactured in accordance with the present inventionshown here to illustrate the pin out of the integrated circuit.

[0033]FIG. 24 is a diagram illustrating the hierarchical presentation ofdisplay views used by the present invention.

[0034]FIG. 25 is a display view showing a Loop View having a tree typestructure.

[0035]FIG. 26 illustrates a display similar to the display depicted byFIG. 12, however, a Hub View corresponding to Stack 2, Hub 1 is shown.

[0036]FIG. 27 illustrates a display similar to the display depicted byFIG. 12, however, a Hub View corresponding to Stack 2, Hub 3 is shown.

[0037]FIG. 28 illustrates the display of a management view.

[0038]FIG. 29 illustrates the display of a hardware debug view for usein system diagnosis in accordance with the present invention shown hereto illustrate the appearance of a “Ports” tab screen.

[0039]FIG. 30 illustrates the display of the hardware debug view of FIG.29, however, a “Hub” tab has been selected illustrating the appearanceof the Hub tab screen.

[0040]FIG. 31 illustrates the display of the hardware debug view of FIG.29, however, a “Loop” tab has been selected illustrating the appearanceof the Loop tab screen.

[0041]FIG. 32 illustrates the display of the hardware debug view of FIG.29, however, a “Stack” tab has been selected illustrating the appearanceof the Stack tab screen.

[0042]FIG. 33 illustrates the display of the hardware debug view of FIG.29, however, an “Agent” tab has been selected illustrating theappearance of the Agent tab screen.

[0043]FIG. 34 is a chart illustrating the data object composition ofobjects as used by the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Attention is immediately directed to FIG. 2 which illustrates adigital system generally indicated by the reference numeral 100including a hub 102 which is manufactured in accordance with the presentinvention. It is noted that like reference numbers are used throughoutthe various figures to refer to like components wherever possible.System 100 includes a main loop 104 which uses Fibre Channel protocol.However, it should be appreciated that loops which employ otherprotocols such as, for example, Token Ring and Fibre Distributed DataInterface (FDDI) may benefit from the teachings herein. Loop 104interconnects stations S1 and S2 such that digital data in accordancewith Fibre Channel protocol standards flows around the loop in thedirection indicated by a number of arrowheads. Only two stations areillustrated as being interconnected by loop 104 for purposes ofsimplicity. Hubs, such as hub 102 are configured with ports by whichstations such as S1 and S2 may be connected with loop 104. In thepresent example, port I is used to connect SI while port 2 is used toconnect S2. While the loop typically uses a fiber optic cable to conductthe digital data, the link between a particular port and associatedstation is not necessarily comprised of a pair of fiber optic cables.Accordingly, different forms of adapters (not shown) may be insertedinto the ports, as will be described in further detail at an appropriatepoint below. It should also be mentioned the interconnection or linkbetween each station and the hub is illustrated as being quite short inthe present figure for illustrative purposes only and, in fact, the linkmay be quite long. Moreover, each station, including its interconnectionwith the hub and aforedescribed adapter, may be referred to as a lobe onthe loop.

[0045] Still referring to FIG. 2, in accordance with the presentinvention, hub 102 includes a first embodiment of a highly advantageousdiagnostics arrangement generally indicated by the reference number 106.Arrangement 106 is made up of a Fixed Diagnostics Unit (FDU) 108 and aRoving Diagnostic Unit (RDU) 110. It should be appreciated that the FDUand RDU may be configured in a number of different ways in view of thisoverall disclosure. In FIG. 2, FDU 108 is illustrated in a form whichallows it to listen to the digital data flowing around loop 104 at asingle point 112 on the loop. RDU 110 is illustrated in a functionalmanner. That is, RDU 110, in the present embodiment, is shown as beingconnected with port I via a pair of dashed lines 114. However, in thisembodiment, the RDU may be commutated selectively between the variousports as indicated by an arrow 116. As shown, the RDU is connected insuch a manner as to listen to the data present at a port output point118. By the term “listen”, non-intrusive monitoring is meant. That is,data present at the point being monitored is observed, but operation ofthe system is not affected in any way. In view of the foregoingdiscussions related to FIG. 1 and specifically considering the use of ananalyzer, it should be appreciated that the configuration of diagnosticarrangement 106 is highly advantageous. For the moment, it is sufficientto say that the advantages provided by this arrangement primarily derivefrom the ability to listen at a plurality of points distributed aroundloop 104. Furthermore, arrangement 106 is considered to be highlyadvantageous due to the fact that information is obtained and gatheredat one location (i.e., within the hub) from all of the monitored points.In this manner, by using features of the RDU and FDU to be described,diagnosis may be performed in view of the system as a whole. Applicantsare unaware of this capability heretofore. As mentioned above, loop 104may have different data present at any of the points between differentpairs of the stations distributed around the loop. Therefore, it hasbeen extremely difficult in the past to gain a full understanding ofproblems such as those described with regard to FIG. 1. The presentinvention serves to alleviate these problems by initially recognizingthe need for collection of data from points distributed around the loopand, thereafter, subjecting this data to analysis.

[0046] Referring now to FIG. 3 in conjunction with FIG. 2 and havingdiscussed several basic concepts of the present invention from aconceptual standpoint with regard to the first embodiment of the presentinvention using hub 102, a specific implementation of hub 102 will bedescribed as depicted in FIG. 3. For purposes of clarity, hub 102remains connected with stations S1 and S2 as is also shown in FIG. 2.For reasons which will become evident, this hub implementation will bereferred to hereinafter as the diagnostic loop or inner loopconfiguration. Accordingly, the diagnostic loop configuration of hub 102includes a highly advantageous diagnostic loop 130 which is submitted tobe unknown heretofore. It should be noted that digital data traveling onthe diagnostic loop travels in a direction which opposes the directionthat data travels on main loop 104 for reasons given below. Thediagnostic loop and main loop each pass through port control circuitsPCC1 and PCC2 associated with ports 1 and 2, respectively. PCC1 isindicated by the reference number 140a while PCC2 is indicated by thereference number 140b. Each PCC includes a LOOP_IN (hereinafter LI) anda LOOP_OUT (hereinafter LO) connection interfaced with main loop 104.DIAG_IN and DIAG_OUT (hereinafter DI and DO, respectively) connectionsrefer to the interface points with diagnostics loop 130. Further, eachPCC includes PORT_IN and PORT_OUT (hereinafter P1 and P0, respectively)connections. When the input or output connection of a particular PCC orthe PCC itself is referred to, the appropriate port number designationwill hereinafter be appended to the foregoing abbreviations. Inaddition, the RDU is interfaced in the diagnostics loop using RDU_IN andRDU_OUT connections. The port control circuits include a number ofhighly advantageous features. One important feature resides in theability of the PCC's to listen to the data present on main loop 104.That is, the data on the main loop is copied onto the diagnostic loop byone of the PCC's and, thereafter, travels around the diagnostic loop toRDU 110 in a non-intrusive manner such that operation of main loop 104is not affected, thus implementing the capability contemplated by thepresent invention requiring non-intrusive monitoring.

[0047] Referring to FIGS. 3 and 4, details regarding the design of thePCC's will now be described. PCC's have been produced in accordance withthe present invention as integrated circuits per the block diagram ofFIG. 4 which illustrates a PCC generally indicated by the referencenumeral 140. PCC 140 will be described primarily in terms of this blockdiagram since it is considered that one of ordinary skill in the art mayproduce this circuit in view of this overall disclosure. PCC 140includes a plurality of signal drivers several of which are indicated bythe reference number 142 (not all drivers are indicated). One by twomuliplexers 144a-c, a one by four multiplexer 146 and a Clock DataRecovery Section (CDR) 148. The latter is connected with a low passfilter section 150 indicated within a dashed line. CDR Section 148serves to recover clock information from incoming data on PORT_IN andretime incoming data to this recovered clock. With regard to details ofconstruction of PCC 140, it is important to note that the data pathsdefined by the circuitry are high frequency in order to carry thecontemplated gigabaud per second data rate. Input and output lines havebeen labeled consistent with FIG. 3. Thus, LI (LOOP—IN), LO (LOOP-OUT),PI (PORT-IN), PO(PORT-OUT), DI (DIAG-IN) and DO (DIAG-OUT) are readilyidentifiable. Additionally, a number of selection/control lines arepresent including CDR_SELN, DIAG_SELN, LOOP_SELN, PORT_SELON andPORT_SELN. The functions of these various additional lines will becomeevident below. TABLE 1 Signal Selection (boldface type is recovereddata) PORT_(—) PORT_(—) LOOP_(—) DIAG_(—) CDR_(—) PORT_(—) LOOP_(—)DIAG_(—) STATE SEL0N SEL1N SELN SELN SELN OUT OUT OUT 1 1 1 1 1 1 LOWLOW LOW 2 0 1 1 1 1 LOW LOW LOW 3 1 0 1 1 1 LOW DIAG_IN DIAG_IN 4 0 0 11 1 LOW LOOP_IN LOOP_IN 5 1 1 0 1 1 LOW LOOP_IN LOW 6 0 1 0 1 1 LOWLOOP_IN LOW 7 1 0 0 1 1 LOW LOOP_IN DIAG_IN 8 0 0 0 1 1 LOW LOOP_INLOOP_IN 9 1 1 1 0 1 LOW LOW DIAG_IN 10 0 1 1 0 1 LOW LOW DIAG_IN 11 1 01 0 1 LOW DIAG_IN DIAG_IN 12 0 0 1 0 1 LOW LOOP_IN DIAG_IN 13 1 1 0 0 1LOW LOOP_IN DIAG_IN 14 0 1 0 0 1 LOW LOOP_IN DIAG_IN 15 1 0 0 0 1 LOWLOOP_IN DIAG_IN 16 0 0 0 0 1 LOW LOOP_IN DIAG_IN 17 1 1 1 1 0 LOWPORT_IN PORT_IN 18 0 1 1 1 0 PORT_IN PORT_IN PORT_IN 19 1 0 1 1 0DIAG_IN PORT_IN PORT_IN 20 0 0 1 1 0 LOOP_IN PORT_IN PORT_IN 21 1 1 0 10 LOW LOOP_IN PORT_IN 22 0 1 0 1 0 PORT_IN LOOP_IN PORT_IN 23 1 0 0 1 0DIAG_IN LOOP_IN PORT_IN 24 0 0 0 1 0 LOOP_IN LOOP_IN PORT_IN 25 1 1 1 00 LOW PORT_IN DIAG_IN 26 0 1 1 0 0 PORT_IN PORT_IN DIAG_IN 27 1 0 1 0 0DIAG_IN PORT_IN DIAG_IN 28 0 0 1 0 0 LOOP_IN PORT_IN DIAG_IN 29 1 1 0 00 LOW LOOP_IN DIAG_IN 30 0 1 0 0 0 PORT_IN LOOP_IN DIAG_IN 31 1 0 0 0 0DIAG_IN LOOP_IN DIAG_IN 32 0 0 0 0 0 LOOP_IN LOOP_IN DIAG_IN

[0048] Attention is now directed to Table I in conjunction with FIGS.3-5. Table 1 indicates signal selections made using any PCC for a numberof different combinations of inputs on the selection lines of that PCCwhile FIG. 5 is a cutaway partial view of the system which primarilyshows the PCC's. It should be appreciated that the relatively largenumber of selection possibilities (i.e., states), evidenced by Table 1,provides a great deal of flexibility in the use of the PCC's. As anexample, normal loop operation occurs in state 28 in which LI isconnected to PO and PI is connected to LO. PCC1, in FIG. 5, is connectedin this way as indicated using curved lines 160 such that data passesfrom the main loop through PCC1, out to the associated station, back tothe PCC and then back onto the main loop. Such a station is “inserted”in the loop. Also, in-state 28, DI₁ is connected directly to DO₁ by aline 162. The purpose of this diagnostics loop connection will becomeapparent. The flexibility of the PCC becomes evident when one observesthat in state 20, like state 28 LI is connected to PO and PI isconnected to LO such that data passes through a station wherein thestation serves as part of the main loop. S2 is illustrated in state 20having curved lines 160 interconnecting the main loop with S2.Furthermore, PI₂ is connected with DO₂, as illustrated by a curved line164, such that loop data from S2 is placed onto the diagnostics loop aswell as continuing along the main loop. Thus, state 20 provides forplacing data from PI (i.e., the output of the lobe on which the stationresides, onto the diagnostics loop, while state 28 provides for routingthe diagnostics loop through the PCC. In this way, data from a station“upstream” (i.e., S2 here) in the diagnostics loop relative to thestation being monitored is able to flow to the RDU for analysis. Whileonly two ports/stations are illustrated in the present figure, it shouldbe appreciated that data may pass through any number of PCC's on thediagnostics loop in this manner.

[0049] Still considering options presented by Table 1 with reference toFIGS. 3 and 6, it is also important to observe that the RDU may placedata onto the diagnostics loop for receipt by the PCC's or, morespecifically, by a selected one of the stations. For example in FIG. 6,if the RDU is to perform diagnostics on S1, PCC1 may be placed intostate 23, such that DI is connected to PO as represented by a curvedline 166, LI is connected with LO as represented by a line 168 and PI isconnected with DO as represented by curved line 164. It should beappreciated that, in state 23, S1 is effectively removed from the mainloop. At the same time, S2 is placed into previously described state 28such that S1 is effectively placed in the diagnostics loop while S2remains connected in the main loop and, as such, may operate normally.With the stations in this configuration, diagnosis of S1 using the RDUmay proceed in a highly advantageous manner, completely isolated fromthe main loop. Hereinafter, testing of a module in the above describedmanner will be referred to as an RDU station diagnosis test. Otherstates of interest from Table 1 include state 22 and state 7. State 22allows external loopback of data back to a station with the station outof the loop, while listening to the data with the RDU. This allows foroffline diagnostics and is used to support a lobe verification testperformed prior to station insertion, as will be described below. State7 allows for internal loopback testing of a PCC using the RDU tosend/receive data for use in hub self testing. It is noted that, in theevent that an internal loop-back test is not successful, hub replacementis commonly indicated since the hub is not generally user serviceable.Further details will be provided below regarding the design of PCC's inaccordance with the present invention.

[0050] With reference to FIG. 7, attention will now be directed to otheradvantages of the present invention. System 100 is depicted during aninitialization procedure performed in accordance with the presentinvention. Accordingly, it will be assumed for purposes of the presentexample that S2 is the object of a port insert. That is, S2 has possiblyjust been received within port 2 of hub 102 and wishes to be insertedinto main loop 104 necessitating a loop reintialization. An RDU stationdiagnosis test is performed on S2. This process (not shown here) beginsin a first step by verifying that S2 has valid Fibre Channel data byconnecting S2 in state 23 and S1 in state 28. While these connectionsare not specifically illustrated in FIG. 7, the reader is referred toFIG. 6 showing S1 in state 23 and S2 in state 28. It should beappreciated that a signal sent from the RDU to S2 will pass throughPCC2, then through S2, back onto the diagnostics loop, through S1 toarrive back at the diagnostics loop. Having received the signal back,this first step performed by the RDU has been satisfied. That is, atthis point the RDU knows by performing the RDU station diagnostic testthat S2 has valid data input and so is ready to connect S2 into the mainloop.

[0051] Still referring to FIG. 7, as a second step, S2 is connected intothe main loop and the monitoring point for the RDU is moved to PCC1.Accordingly, PCC1 is placed into state 20 (described above), asindicated by curved lines 180 within PCC1, while PCC2 is placed intostate 19, as indicated by curved lines 182, in which DI₂ is connected toPO₂ and PI₂ is connected to LO₂ as well as to DO₂. With thisarrangement, the RDU can transmit a LIP to S2 via a segment 183 of thediagnostics loop and PCC2. PCC2 (assuming proper S2 operation) receivesa response LIP back from S2 and places it onto a main loop segment 184on which the LIP travels to PCC1. At the latter, the LIP is routedthrough S1 and then onto DO₁ to travel back to the RDU on a segment 186of the diagnostics loop. In this way, it can be verified by the RDU thatthe LIP transmitted into S2 is received at S1. Having verified that theLIP has successfully traveled through all of the stations on the loop,the RDU may allow completion of the S2 port insert. In this regard, itshould be appreciated that counter-rotation of the diagnostics loop inrelation to the main loop is advantageous. As one advantage, thiscounter-rotation allows the port undergoing an insert to first receivethe LIP from the RDU in a manner that is consistent with intuition.Thereafter, the LIP travels through all of the remaining stations on theloop. As another advantage, it is submitted that the counter-rotatingdiagnostic loop allows insertion of ports according to Fibre Channelloop protocol and that, without this feature, the port insert could benon-compliant. Moreover, if the diagnostics and main loops rotate in thesame relative direction and the port to be inserted first receives theLIP (not shown), a segment conflict occurs on the diagnostics loop,which has not been illustrated for purposes of brevity, but which isreadily demonstrable by one of ordinary skill in the art in view of thisdisclosure.

[0052] Referring now to FIG. 8, another highly advantageousinitialization procedure performed in accordance with the presentinvention will be described. Specifically, an automatic externalloop-back test is performed during any port insert. FIG. 8 is a partialview showing S1 as part of system 100. The external loop-back test isdepicted under way for S1 with S1 in state 22 from Table 1. State 22connects PI₁ to PO₁ and to DO₁ while connecting LI₁ to LO₁, as indicatedby a set of curved lines 184. It should be appreciated that the externalloop-back test provides for verification of the entire lobe on which S2resides including the lobe's complex high frequency paths. In fact,because the diagnostics loop is used for monitoring, the integrity of atleast a portion of the diagnostics loop is also confirmed. It issubmitted that Fibre Channel protocol is completely devoid of thisfeature, including the automatic implementation contemplated herein.Moreover, Applicant's are not aware of the provision of an automaticexternal loop-back test in any form of loop protocol that provides forsimultaneous monitoring of the looped back data. Such an externalloop-back test is effective in the diagnosis of a problem with PCC1. Aparticular advantage associated with this procedure resides in the factthat the procedure is performed by the unit itself in a rapid mannerwhich is likely to be of great benefit to a system administrator. Forexample, a system administrator can be notified via a notificationgenerated by the system following a failed port insert, while the failedport is held in bypass mode. This notification may be generated in theform of an email message which is particularly advantageous in instanceswhere the system administrator is monitoring from a remote location.

[0053] Referring briefly to FIG. 2, it should be appreciated that thepresent invention may be implemented in an alternative embodiment (notshown) wherein “Port Diagnostics Units” (PDU's) are provided. That is,the combination of the FDU, RDU and diagnostics loop is replaced infavor of a PDU at each port. In this manner, loop data can actually betracked during its progress around the main loop by the PDU's. It iscontemplated that a PDU implementation of the present invention ispractical particularly in the form of an ASIC in which the entire hubfunction is produced essentially as one chip. The introduction of thePDU implementation does not vary the basic concept of the presentinvention. That is, the advantages derived herein extend from thecapability to “listen” at a plurality of points distributed around themain loop. A further advantage is provided, as mentioned, in the form ofthe ability to simultaneously listen to the distributed loop points. Forexample, the progress of a specific, individual ordered set can betracked in its progress around the loop.

[0054] Having generally described several hub implementations inaccordance with the present invention, details with regard to thediagnostics capabilities of the RDU and FDU will now be described. Itshould be appreciated that these capabilities may also reside in a PDUimplementation. One feature incorporated in the RDU and FDU is orderedset detection. Fibre Channel protocol recognizes ordered sets as fourten-bit characters (FC-0). Ordered sets are used, for example, duringloop initialization. The present invention monitors a particular groupof ordered sets. This monitored ordered set group includes IDLE, LIP,LIP F7, LIP F8 (where LIP is Loop Initialization Primitive), SOF (Startof Frame), ARB (Arbitrate) and OPN (Open). In addition, any other validordered set may be specified as USR (User) as well as an Unknown orderedset and K28.5 (comma character) which is the first character that anyordered sets may have in common and, therefore, is useful in adetermination that valid ordered sets are present. A number of featuresare related in a direct way to the ability to perform ordered setdetection at the points distributed around the loop, at least one ofwhich will be described immediately hereinafter.

[0055] Turning to FIGS. 7 and 9, the present invention provides afeature related to the operational state of a Fibre Channel loop. Thisfeature is presently implemented in both RDU 110 and in FDU 108.Presently, five loop states are used herein including INOPERATIVE (theloop is down), INITIALIZING, OPEN-INIT, UP and UP+FRAME (loop is up,with frames). The loop is considered as operational in either of the UPand UP+FRAME states. In FIG. 9, a view is provided which isrepresentative of the physical appearance of the back of hub 100. Inaccordance with the present invention, a loop status indication LED 200is provided which is illuminated whenever either of the loop states UPor UP+FRAMES are determined to exist. The presence of each of these twostates is established using ordered set detection in conjunction withtwo additional detectors. The first additional detector detects anordered set that is unknown and, hence, is referred to as an UNKNOWNdetector. That is, the unknown ordered set is a valid ordered set but isnot a member of the monitored ordered set group which is detected. Thesecond additional detector is referred to as a LINK-USEABLE detector. Inaccordance with Fibre Channel protocol, more than a certain number ofones or zeros cannot occur in sequence. This certain number specifies atransition density which is a crude indication of invalid characters onthe loop. Irrespective of ordered set detection, loop up indicator 200is not illuminated unless the transition density has not been violatedper the LINK-USEABLE detector. That is, if the link is unusable, theloop is said to be down. If no valid ordered sets are detected includingthe set specified by the UNKNOWN detector, the loop is also consideredas being down.

[0056] The present invention recognizes that a Fibre Channel system willgo to loop up in a sequence of ordered states that is identified throughthe use of the aforementioned monitored ordered set group. It should beappreciated that the monitored group of ordered sets will appear insequence as a system moves from the inoperative state to an operativecondition and that sequence must occur for proper initialization.Specifically, the first set which is monitored for from an inoperativestate is a LIP. Upon recognition of a LIP ordered set, the INITIALIZINGstate is entered. In the INTIALIZING state, an arbitrate (ARB) or SOFordered set is anticipated. Once an ARB or SOF is seen, status moves tothe OPEN−INIT state. Thereafter, a CLS (close) command is anticipatedwhich is used as a transition to the UP state. It is noted that theclose command does not appear in the monitored set group, but isconsidered as a companion ordered set of the OPN command for use inclosing a connection. Arrangement 100 then monitors for data frames(UP+FRAME) by detecting SOF. Thus, once the proper sequence of orderedsets has occurred, indication is provided, for example, via LED 200.Alternatively, the system administrator may sreceive an indication viasoftware.

[0057] Another ordered set detection feature that is implemented in RDU110 is a counter (not shown) that will count any ordered set for whichinformation is desired to be gathered. For example, the counter cancount frames at a particular port. If the counter is left active for aparticular period of time, the number of data frames sent over thatperiod is detected. In this way, traffic or events of interest can bemonitored. Of course, if the data of interest is known to pass all theway around the loop, the RDU may be set to any monitoring point. Asanother example, the system administrator may wish to determine how muchor how often a particular station is using the loop. Assuming that thesystem administrator wishes to establish this information for a stationS7 (not shown) assigned ALPA-7, the counter can be set up to count ARBsor startup frames from S7. In this regard, it should be appreciated thatordered sets are 40 bits in length. The first 20 bits indicate what typeof ordered set it is, while the next 20 bits give further details aboutthe ordered set which usually includes the address of the station theordered set came from. Accordingly, the counter can be set up to eitheruse the ordered set just in terms of its type or to use the ordered setbased on all or nearly all of the information available from the 40bits. For example, only ARB ordered sets from S7 could be counted or, asanother example, only ordered sets from S7 “talking” to a station S4could be counted (not shown).

[0058] Another feature in accordance with the present invention residesin the ability to capture Arbitrated Loop Physical Addresses (ALPA's) byobserving data patterns or communications on a loop. It is noted thatthe ALPA's are assigned to the various stations that are present on theloop during initialization. More specifically, present duringinitialization states referred to as OPEN and OPEN−INIT. Through theability to listen at points distributed around a loop, the presentinvention is capable of determining which ALPA's are attached to eachport. That is, an ALPA map can be generated. There are two methods usedto establish the ALPA's connected to each port. In a first method, anARB command is used. It should be appreciated that the use of ARBcommands can reveal all of the active ALPA's on the loop while listeninganywhere on the loop.

[0059] Referring to FIG. 3, in a second method of mapping connectedALPA's, an OPN command is used. When using OPN commands for thispurpose, the listening point is moved around the loop to establish inwhich domain the OPN exists (i.e., where the OPN vanishes). For example,if S1 has an assigned ALPA of 1 and S2 has an assigned ALPA of 2, RDU110 could first listen at S1. By examining ALPA's with ARB commands,ALPA-1 and ALPA-2 will be seen. Using the OPN ALPA mapper presentlyunder discussion, however, only OPN's for ALPA-2 will be seen.Similarly, if the listening point is switched to S2, only OPN's forALPA-1 will be seen. The disappearance of the OPN infers that thestation at the listening point is assigned that ALPA. Certainty as tothat being the correct ALPA is increased, as time passes, when that ALPAcontinues to be absent at that point. In this regard, a PDUimplementation (not shown) is advantageous since the progress of an OPNaround the loop can be observed simultaneously at all of the pointsaround the loop. In this way, certainty is increased as to where an OPNdisappears.

[0060] Having introduced the reader to a number of concepts of thepresent invention, an appropriate juncture has been reached at whichsome of its advantages can be emphasized. Specifically, it is importantto understand that all of the capability discussed is provided in thehub itself. That is, the need for an external analyzer has beenvirtually eliminated. At the same, time, however, an external analyzeris inherently handicapped since its monitoring is intrusive, asdescribed above. The present invention is inherently powerful based onthe capability to monitor a plurality of points distributed around theloop. Other features such as, for example, ordered set detection and thecounter are extremely useful in conjunction with this multi-pointmonitoring capability. It is submitted that such a combination offeatures has not been seen heretofore. In terms of problemidentification, analysis can first be performed on the data to evaluatewhether or not there really is a problem. In this regard, there can beconditions that are part of the normal operation of the loop, however,if these conditions persist, then they are a problem. Such problems canbe identified with the multi-point data available through consolidationof information. From another viewpoint, the multi-point data is used toestablish the status of each of the stations in the loop. A particularstation or even the hub itself can be identified as the source of aproblem. With status data as to the entire loop including the hub inhand, the status data can be displayed or automatic, predeterminedresponses may be taken. For example, a defect can be removed.Thereafter, operation of the system may resume automatically.Alternatively, an indication can be provided to a system administratorthat the defect has been removed and operation can now be restored. Inone feature to be described, beaconing may be employed to identify theactual physical location of a removed defect. Specific details withregard to the display of additional status information will be providedimmediately hereinafter.

[0061] Referring to FIG. 10, a display 202 is shown depicting a sitemanagement view generally indicated by the reference number 204. Thepresent example assumes a system having two managed stacks wherein stack1 includes two hubs and stack 2 includes three hubs. Site managementview 204 represents an encapsulation of the status of every device thatis within the scope of management. Therefore, at the highest level, allof the managed stacks including stack 1 and stack 2 are indicated by thereference numbers 206 and 208, respectively. Also shown, in the form ofelliptical circles, are the loops (each of which uses a hub) associatedwith each stack as indicated by the reference numbers 210 and 212 forthe stack 1 hubs/loops and by the reference numbers 214, 216 and 218 forthe stack 2 hubs/loops. It should be noted that the operational statusof each loop is indicated by the color of the loop in the present view.For example, an up and operating loop is shown by the color green withinthe corresponding elliptical circle. If any of the loops are not green,further attention should be directed to these loops, for example, usingfurther status display features of the present invention which areavailable by “drilling down” from the site management view. It should beappreciated that one advantage of the site management view resides inimmediately directing the attention of an observer to problem areas,even in the instance of a system administrator having little practicalexperience. In this regard, it is contemplated that the site managementview may be iconified in a way which makes problems apparent via theappearance of an icon.

[0062] Turning to FIG. 11 in conjunction with FIG. 10, selection ofstack 2, for example by double clicking on it in the site managementview of FIG. 10, brings up a stack view 220 on display 202. It is notedthat hubs may be considered as being in the same stack by virtue ofhaving some type of connection with regard to their managementinformation. For example, the connection may comprise an out of bandmanagement cable. That is, this management data is not present on theloops themselves. Stack view 220 displays hubs 214, 216 and 218 (FIG.10) labeled as Hub 1, Hub 2 and Hub 3, respectively. The stack view isintended to highlight information from a configuration standpoint. Forexample, what types of physical connections are present in each hub andwhether these connections are optical (shortwave or longwave) or copper.These connection types will be discussed further at appropriate pointsbelow. In addition, it is indicated which of the hubs may possibly havemanagement agents in them since the management agent is what providesthe information used to make these determinations. A color indicator 222(the color of which cannot be seen due to format limitations of thepresent application, as is the case throughout the figures) comprisingthe background of the stack indicates an overall status derived from thestatus of each hub. For example, the background is green if all of thehubs are fully functional.

[0063] Referring to FIGS. 9-12, selection of one of the hubs in stackview 220 leads to a hub view 224 associated with the selected hub. FIG.12 illustrates this view for Hub 2 of stack 2 (indicated by referencenumber 216 in FIG. 10). It is noted that additional Hub Views will beprovided below. Hub view 224 may also be referred to as a back-of-boxview since the image is intended to physically represent the appearanceof the corresponding panel on the hub itself. It is noted that a greatdeal of the information available through the use of the presentinvention is presented in the hub view. At a glance, any of the portscan be seen including whether each port is in a functional status.Alternatively, it is indicated that ports need attention or a port is ina failure mode. This indication is provided by the background color 226surrounding each port in gray, green, yellow or red (as noted above,color not illustratable) where gray indicates unused, green indicatesfunctional, yellow indicates the need for attention and red indicatesfailure. Additionally, a pair of virtual LED's 228 are illustratedassociated with each port. The actual LED's corresponding to thesevirtual LED's are indicated by the reference number 230 in FIG. 9showing a pair of LED's is associated with each port. It is noted thatboth virtual LED's 228 and actual LED's 230 can be beaconed to cause theLED's to blink on display 202 as well as on the hub box itself, as willbe further described. Thus, a good or bad indication can be provided foreach port of the hub based on monitoring in accordance with the presentinvention. This feature is advantageous, for example, to anyone inhelping to locate hardware of interest. In this regard, it is submittedthat the capability to reflect the status of the loop and the use ofbeaconing, as described, have not been seen heretofore. It is also notedthat a virtual “Loop Up” LED 232 is provided which corresponds to LED200 in FIG. 9. That is, virtual Loop Up LED 232 is illuminated wheneverLED 200 on the hub panel is illuminated. Other indications include PowerOK 234, uC (microcontroller) OK 236 and Fan Fault 238 for which theactual and virtual LED's are indicated using the same reference number.

[0064]FIG. 13 represents a port detail screen 240 which appears uponselecting one of the ports in FIG. 12. In this example, port 11 of hub 2in stack 2 has been selected. A port control box 242 is included in thescreen which provides four selectable modes under which the port can beoperated. The auto mode is configured for maintaining loop integrity andenabling built in recovery functions at a policy level. That is, in theauto mode, ports will not be inserted that will bring the loop down. Theauto mode gives the hub full license to make every port insertion gothrough criteria to maintain loop integrity. In effect, authority isgiven to screen every module such as, for example, a GBIC (GigabitInterface/Interconnect Converter) that is plugged into this port priorto its insertion into the loop. That authority is removed, for example,if the Force Bypass mode is selected. In Force Bypass mode, the portwill not be inserted irrespective of validity. The Force Bypass mode canbe used to perform tests on an already inserted port or a port can bebypassed prior to its initial insertion. It is noted that otherdiagnostic capabilities can be invoked in the Force Bypass mode, as willbe described. Several other modes can be invoked including Loopback andForce Insert. In the Loopback mode, the port receiver is connecteddirectly to the port transmitter such that a station on the port may dodiagnostic self testing (see, for example, FIG. 8). In a lobeinitialization feature which represents an alternate and more powerfulmethod for testing stations before insertion, the loopback capabilitybuilt into the port is used to wrap receive back to transmit so as tocause the station to initialize completely before insertion. Thisfeature has the advantage of providing much more confidence that theinserting station is fully functional before impacting the hub and allstations already attached. In the Force Insert mode, a node/station isinserted into the loop irrespective of its operational status. Such afeature may be useful if a node is not behaving well according to theFibre Channel protocol and it is desired to force that node to beinserted into the loop for observation. For example, the node may not begoing through proper initialization. The provision of all of these userselectable modes is highly advantageous with regard to giving the userfull control over devices for purposes such as, for example,troubleshooting. In this regard, verification can be performed ondevices that are being blocked out for reason of not behaving well. Thatis, a suspect device can be reinserted to observe whether or not it isbringing down the loop.

[0065] Still referring to FIG. 13, one feature present in the portdetail view is a GBIC display box 244. It is noted that GBIC's have somebuilt in identification information. This information is extracted fordisplay here. The information identifies the specific type of GBIC. Forexample, a shortwave laser GBIC (as shown), a longwave laser GBIC or acopper GBIC with an HSSDC connector. A state indication 245 within GBICdisplay box 244 is obtained from both the GBIC and the diagnosticcircuitry that is monitoring the port, as described above. A “No ValidData” indication is illustrated. In this way, it is determined if thereis a valid signal and whether or not the node is transmitting validFibre Channel characters. A port connect box 246 includes a stateindication 248 that is produced by the present invention. While actioncan be initiated based on no valid data, the present invention furtherprovides for bypassing a node that is in a loop failure state ortransmitting LIP F8. For example, if a device is “LIP F8ing”, portconnect state box 248 will reflect that condition (not shown).Alternatively, if there is a problem with the transmitter on the GBICitself, it will be indicated.

[0066] Referring to FIG. 14, if Vixel logo 250 is selected in the hubview of FIG. 12, a hub sweep view 260 appears on display 202. The hubsweep view is comprised of a consolidated capture of data for all of theports of the hub displayed in a meaningful way. Data is displayedcorresponding to each port or node on the loop. The port numbers areindicated in a row 264. Beneath each port number is a column of boxeslabeled to the far left with ordered sets. It should be noted that themonitored group of ordered sets, described above, is displayed forming amajority of the information in the column. Specifically, LIP isindicated by reference number 265, LIP F7 is indicated by 266, LIP F8 isindicated by 268, OPN is indicated by 270, ARB is indicated by 272, IDLEis indicated by 274, SOF is indicated by 276, USR (User Defineable) isindicated by “Match” at 278 and the Other ordered set (Other OS) isindicated by 280. A link useable indication 282 is provided along with aK28.5, comma character, indication 283. Therefore, the presence of anordered set associated with each port may be indicated. It should beappreciated that, while quite a number of individual data are displayed,a system administrator can discern meaningful information from thedisplay very readily. Even an inexperienced administrator willimmediately recognize the value in this display. An experiencedadministrator, however, will be capable of correlating the data in viewof his or her experience. Other displayed data includes a loop statedisplay 284 which indicates whether the loop is up, down orinitializing. Presently, an “Up” indication is being given. It is notedthat the various display boxes of FIG. 14 may be arranged in anysuitable manner and that a warning will come up if a user selects annon-automatic option.

[0067] With regard to interpretation of sweep display 260, initializingis a normal process that a loop will go through as the loop is startingup. Initialization should occur for a very brief period of time prior tothe loop coming into the up or active state. If the loop stays stuck ininitialization, the hub sweep view enables one to be able to see whichnodes/ports are involved. More particularly, the presence of LIP F8 isdisplayed. The significance of this loop initialization primitive wasdescribed earlier. Therefore, if a node is in a LIP F8 state, from thissweep view one can readily see which is the offending node. Thereafter,mechanisms also built into the hub can be used to automatically recover.It should be appreciated that this display is highly advantageous sincefor each segment of the loop one can, at a glance, see exactly whichdata is being transferred. That is, if that segment is in a quiet state,if it's in initializing or if it's in a failure mode. Alternatively,further troubleshooting may be performed using other diagnostic screensto be described below. In this regard, the present invention provides agreat deal of single port visibility through the monitoring that can beperformed on a single port. By collectively displaying data gathered forall of the ports in a consolidated view, valuable information isprovided as to what is actually going on in the loop. It is submittedthat such a view is highly advantageous and has not been seen in a FibreChannel system heretofore. In order to achieve a display such as this inthe prior art, the number of ports would at least have to be doubledwith analyzers residing at each of the added ports. Sweep display 260has further implications. That is, by having the information availablefrom the present invention, automatic actions can be implemented basedon analysis of the data accumulated. It should be mentioned that sweepdisplay 260 may be presented irrespective of whether a port or rovingdiagnostic implementation is used to collect the data.

[0068] Referring to FIGS. 15 and 16, one example of a per portdiagnostic screen 286 is illustrated. Port diagnostic screen 286includes a port diagnostics control box 288, a port selection box 290and a transmitter control box 292. Using port diagnostics screen 286, itshould be appreciated that full path end-to-end verification can beperformed from the hub on a lobe. As an example, FIG. 16 illustrates aportion of hub 102 connected with station S1. The lobe consists of theGBIC transceiver which includes a transmitter TX_(P1) and a receiverRx_(P1). The lobe further includes a cable or fibers 294 extending fromthe hub to a node receiver Rx_(S1) and a node transmitter Tx_(S1) at thestation. The latter may also include a loop state machine 296 that isdiagrammatically indicated by an arc extending between the stationtransmitter and receiver. It is noted that during the full pathverification, the hub bypasses the station, as illustrated (by LI₁ beingconnected to LO₁), such that the node is isolated from the main loop. Inthe absence of loop state machine 296, data that is sent to the stationfrom the hub is expected to return to the hub so as to perform anend-to-end connection verification. In the presence of loop statemachine 296 and being cognitive of the loop state machine implemented,however, an ordered set can be sent to the station which should return adifferent response. Thus, the operation of the loop state machine isverified as well as the connections in the lobe. The ability is providedto transmit to a port, receive on that same port and detect what orderedsets were seen on the receive. Lobe verification is highly advantageouswith regard to diagnosis since there are numerous opportunities forpoints of failure around the lobe's path. For example, there may be abad laser or a plug-in connection that is not fully seated. It should beappreciated that this verification is more powerful as compared with anexternal loop-back test. In an external loop-back test (not shown), thestation itself may do some verification with the port in bypass mode.The node would initiate the process and would transmit from Tx_(S1) toRx_(P1). The hub will then loop that data to Tx_(P1) to then pass theinformation back to S1 via Rx_(S1).

[0069] The end-to-end lobe verification test of the present invention isconsidered to be highly advantageous (1) in verifying the node statemachine without external interaction and (2) because the configurationon which the verification is successfully performed will not bephysically disturbed for purposes of entering normal operation. That is,the configuration will not be disturbed upon entering normal operation.It is submitted that this feature has not been seen heretofore. Whileport diagnostics screen 286 provides a visual display for purposes ofmanipulating this lobe verification, the present invention contemplatesthe use of lobe verification in an automatic process. For example, acapability may be provided for an operator to do a full configurationverification by pushing one button. In response, the system would thengo out, bypass every node and do the full path verification on eachnode. Thereafter, a display (not shown) of the configurationverification results can be provided.

[0070] Still referring to FIGS. 15 and 16, another capability isprovided using transmitter control box 292. Through the ability to turnhub transmitter Tx_(P1) on and off, another form of verification isprovided. Specifically, node verification is provided in response toturning the port transmitter off to a node. If Tx_(P1) is turned off, S1should respond with a LIP F8, or the loop failure character, thus,serving as another mechanism of verification. The capability toselectively turn off a transmitter whereby to solicit a LIP F8 from aconnected station may be referred to hereinafter as a transmit disablefeature and is considered as being highly advantageous.

[0071] Turning now to FIG. 17, a Fibre Channel system 300 is illustratedwhich includes stations S1-S5, a hub H1 and a loop L1. Stations S1 andS2 are connected in L1 while Stations S3-S5 are connected using H1. Forpurposes of the present example, it will be assumed that two tape backupoperations are occurring in which S3 and S5 are both tape devices and S1and S2 are servers. One backup is from S1 to S3 while the other backupis from S2 to S5. It should be appreciated that Fibre Channel is not abroadcast media. That is, without the hub of the present invention,there is no visibility to all data at all points in a loop. In addition,only two devices can be “talking” at once to each other using a loop.This holds with the aforementioned tape backups going on, since only twonodes can have control of the loop and be transferring data at any onetime. Therefore, the two backup operations are in total contention forthe bandwidth of the loop at this point in time. Assuming further thatH1 is manufactured in accordance with the present invention, at leastthe ordered sets described above can be counted. Startup Frames (SOFs),for example, show data going through while ARBs show a node gainingcontrol of a loop. By looking at these specific pieces of data, anindication may be provided that there is contention or as to the amountsof data that are being transferred such that, upon analysis of the data,recommendations can be made to either change the time assigned for oneof the backups or to segment one backup onto another loop (not shown)since the simultaneous backups tend to slow one another down, as well asto prohibit any other use of the system. In essence, this feature isprovided by using gathered information to give one a picture of thetraffic or the data frames between the modules on the loop.

[0072] Still referring to FIG. 17, it is important to understand thatinformation relating to S1 and S2 is provided despite the fact that loopL1 is not managed. In other words, determinations are made regarding ahub or a loop in which H1 is not actually physically directly monitoringthe information on that remote loop or hub. These determinations as tothe utilization of the remote loop can be made, however, because the hubof the present invention is connected to the remote loop. Utilizationmay be displayed, for example, in the form of a tachometer style gauge(not shown). Other features may be included such as a threshold foralarming purposes. It should be appreciated that the addition of a hubconfigured in accordance with the present invention is highlyadvantageous when added to an “unmanaged” system. Particularly,diagnostic capability will be provided for the existing installation aswell as for components connected directly to the new hub. In the exampleof FIG. 17, with regard to unmanaged loop L1, managed hub H1 may notnecessarily be able to identify whether it is S1 or S2 that ismisbehaving on the unmanaged loop. However, a problem could certainly beisolated to the port of H1 with which the unmanaged loop is connected.It is submitted that these features with regard to visibility ofutilization and congestion are highly advantageous and have not beenseen heretofore.

[0073] Referring to FIG. 18 and having gone through a number ofdifferent displays, status indications and information displayed, adescription will now be provided regarding details as to how thesefeatures are implemented using a data management arrangement 320.Initially, information is collected by a hub data collection section 322which represents all of the hardware “hooks” that are built into hub 102(FIGS. 2 and 3) manufactured in accordance with the present invention.This information is stored in a data repository 324 that is resident ona management card (not shown) that is built into the hub. The data isstored in an SNMP mid-structure which is a standard managementacquisition tool in networking. It should be appreciated that theavailable data stored in the memory itself provides the advantagesherein (i.e., based on the origination points of the data) inconjunction with its subsequent analysis. The data is transferred via aLAN connection 326 in response to a host poll 327 which is generated bya host system that is not illustrated for purposes of simplicity. It isnoted that host poll 327 and the remaining, as of yet undescribedportions of FIG. 18 relate to the method steps implemented within thehost system. The information is polled in response to a request by anapplication running on the host system. That is, data repository 324serves as an SNMP agent which collects the information in response tothe host request. While FIG. 18 illustrates a poll driven system, itshould be appreciated that an event driven system is also contemplated.

[0074] Referring to FIGS. 10-13 in conjunction with FIG. 18, the hostpolls information from the hub (or hubs) and will poll in an automaticpoll 328 all data generically unless the system is in a diagnostic mode.Therefore, the polled information is used in site management view 204(FIG. 10), stack view 220 (FIG. 11), hub view 224 (FIG. 12) and portdetail screen 240 (FIG. 13). The poll of this information is performedat a regular interval which is usually resettable. Generally, theinterval may be set from five seconds to each hour. The information isstatus information which may include, for example, whether a port hasbeen bypassed and if the port has a signal. Thus, the information thatis displayed in FIGS. 10 through 13 is polled continuously. Attributesof the data are assigned to a hierarchy of objects within the system.For example, attributes are assigned to a hub object, a port object or astack object. Each object is based on knowledge of what components theparticular object is composed. That is, a port “knows” that it has asignal and a GBIC may be associated with the port. If another port doesnot have a GBIC, the lack of a GBIC is actually an attribute of thatother port. If a port does have a GBIC, then there are characteristicsof the GBIC that are available. As further examples, a hub is comprisedof ports and a stack is comprised of hubs.

[0075] Referring to FIGS. 10-14 and 18, certain characteristics areobserved in looking at the information that is monitored. For instance,if a port goes into a bypass mode, it should be reported why the portwent into that bypass mode. This forms part of the information that isdisplayed on a regular basis. It should be appreciated that in adiagnostic mode a different type of mechanism comes into play. Forinstance, when the hub sweep view of FIG. 14 is polled up, thisdifferent type of mechanism is employed. While information will still bepolled, control information will be sent as well. Thus, if hub sweepview 260 (FIG. 14) is initiated, the hub will use its detectorarrangement (i.e., RDU or PDU's) to get information for each port suchas the different ordered sets described above. This information will bedisplayed and observed for the presence of a port in LIP F8. If thelatter occurs, an indication is provided that the port transmitting LIPF8 is in a failure status and needs attention. For example, if such aport is in a forced insert mode, the entire loop will be brought down.The status of the port can be reflected all the way up to the loop level(FIG. 10) while, if the port number is displayed, the background of theport is highlighted to reflect status. For the LIP F8 failure status,the background highlight is red. Color highlights are represented inmonochrome form around ports 2, 3, 5, 9, 10 and 11 in FIG. 14. In sum,two forms of diagnostic activity occur. The first is automatic poll 328which is auto-running all of the time while the second is anintrusive/on-demand poll beginning with step 329 that occurs on demand.The automatic poll monitors all components and objects in the systemusing a generic health associated with each. This generic health may bereflected up, for example, with the occurrence of a LIP F8, asdescribed. The on-demand poll is used in more detailed or specificmonitoring (FIG. 14) and will be described in further detailhereinafter. The present invention also contemplates the use ofautomated diagnostics 330, as mentioned above with regard to eventdriven diagnostics.

[0076] Referring to FIG. 18, the on-demand diagnostics operate first bydetecting all ports in step 329 to determine which ordered sets aregoing past each port. In this way, a determination is made as to whetheror not the loop is functional. More specifically, if OPNs, ARBs, andstartup frames (SOF) are going past, these are valid, operational loopordered sets. In contrast, if there are loop initialization primitivesgoing around for longer than a very short period of time (e.g., a secondwould be a long time), the loop is stuck in initialization which will bereflected up through indications. Thus, in step 332, if LIP's occur forgreater than some predetermined interval, health indication is changedin a “change health status” step 334 for display purposes. Othernotification mechanisms may be provided, as well. In step 336, if LIP F8is detected, step 338 changes the health status to the failure mode.While the present discussions are centered upon Fibre Channel, it isconsidered that the method of the present invention can be used in othersystems. That is, the characteristics of the data in a particular systemmay allow provisions for the same sort of detection capability. Forexample, if detection were performed in other protocols such as in anEthernet hub in the disclosed manner (at the bit level monitoringnon-invasively at distributed points), it is submitted that this methodis new.

[0077] As described above, IDLE characters are included in the monitoredgroup of ordered sets. A discussion will now be provided as to a numberof features that are available as a result of idle detection coupledwith the overall monitoring configuration of the present invention.Initially, it is noted that if an idle mode is present (i.e., idles arebeing passed around a loop by the stations connected therein) and acable is cut, for example, to a node, that node or station will begintransmitting LIP F8. In accordance with the present invention, that nodewill automatically be bypassed such that the quiet state of the loop isrestored. In another feature, the presence of essentially nothing butidles on a loop indicate that a loop is not being utilized. If a patterndevelops, for example, every evening between 10 p.m. and 2 a.m. nothingbut idles are seen, an opportunity is provided for performing activitiessuch as backup. Thus, recommendations can be made for these quiet timesto do batch processing so as to better utilize the data link. In stillanother feature, the reader is reminded of the foregoing discussionrelating to detection of valid Fibre Channel characters. If a nodestarts corrupting IDLE characters, the present invention will detect thefact that these are not valid IDLE characters. In response, the nodewhich is corrupting the IDLEs will automatically be bypassed. It shouldbe appreciated that this feature is highly advantageous. By proactivelyintervening upon detection of the corrupted IDLEs and, thereupon,disallowing the offending node from participating, there is no loss ofactual data. Thereafter, a notification may be provided with regard tothe occurrence of the corrupted IDLEs.

[0078] Attention is now directed to FIG. 19 which illustrates a FibreChannel system produced in accordance with the present invention,generally indicated by the reference number 350, for purposes of adiscussion of topology mapping in accordance with the present invention.System 350 includes hubs H1 and H2 manufactured in accordance with thepresent invention. Station S1 is connected to port P1 of H1 whilestation S2 is connected to port P2 of H2 and station S3 is connected toPort P3 of H2. Port P2 of H1 is connected to port P1 of H2 forming a hubto hub connection. It is assumed that ALPA 1 is assigned to S1, ALPA 2is assigned to S2 and ALPA 3 is assigned to S3. It should be appreciatedthat ALPA detection can be applied, as described with regard to FIG. 3,to determine which ALPA's are connected to each port. In the presentexample, ALPA mapping, in and of itself, will correctly show that ALPA1, or S1 is connected to P1 of H1. By running an ALPA map on H2 port 1from H1 port 2, however, ALPA 2 and ALPA 3 (i.e., S2 and S3) will beseen as connected to H1 port 2. In this regard, it is apparent that ALPAmapping does not reveal devices that may be intermediately connectedbetween the stations. Accordingly, it is an objective of the presentinvention to perform topology mapping identifying intermediatelyconnected devices. In one topology mapping feature, the presentinvention includes an arrangement for identifying hubs to other hubssuch that, if two of these managed hubs are connected together, one hubwill recognize that it has a managed hub connected to it and relay thatinformation to a management application. Knowledge of the hub to hubconnection will permit the correct locations of S1 and S2 to beidentified. This feature is facilitated through identification/serialnumbers that are built into the hubs.

[0079] The transmit disable feature described with regard to FIG. 16 ishighly advantageous for use in another topology mapping feature.Specifically, one method used in accordance with the present inventionis to check response to the transmit disable feature. If an attachmentis a station, it will respond with a LIP F8. In other words, receipt ofLIP F8 in response to a transmit disable confirms the presence of astation on the particular lobe served by the disabled transmitter. If,however, a prior art hub rather than a station is on the particular lobeserved, the hub will not respond with LIP F8. Still another topologymapping feature is provided which is also submitted to be highlyadvantageous and which is designed for use with managed hubs inaccordance with the present invention. In this feature, following anattachment request received by a managed hub, the managed hub willtransmit a burst of LIP F7 to the requesting connection prior toinsertion. If the attachment request is from a station, the station willrespond to the burst with LIP F7 followed by a stream of IDLES for 15milliseconds. During the 15 millisecond period, an ARB FB is transmittedto the requesting connection. If the requesting connection is a station,the ARB FB will not return to the hub. Alternatively, if the connectionis a hub, the ARB FB will return to the hub. In the event that the ARBFB is returned, the hub will attempt to exchange serial numberinformation via special ordered sets. If the attaching hub is anothermanaged hub manufactured in accordance with the present invention, aserial number other than the first hub's will return. Conversely, if theattaching hub is an unmanaged hub, the serial number of the first hubwill return. Therefore, one advantage of this feature is the capabilityto gather enough information to describe the sequence of connection ofhubs by serial number. Once the sequence can be detected, it is alsopossible to determine if hubs are connected improperly and reportproblems. It should be appreciated that a significant challenge forsystem administrators concerning complex configurations is to confirmthat the wires/fibers got connected as intended. This level of topologymapping provides the needed feedback.

[0080] In sum, with regard to the topology mapping features describedthus far, ALPA mapping allows determination of the ALPA's that areconnected to a port. The transmit disable feature, in which thetransmitter to the connection is turned off before the connection isallowed on the loop, allows identification as to whether the device onthe connection is a station or another hub. Identification of serialnumbers of other hubs allows for locating managed hubs and providingtheir identification numbers.

[0081] Referring to FIG. 3, it should be appreciated that hub 102 of thepresent invention is a repeated hub. Data comes into the hub seriallyand goes out serially with no delay or imperceptible delay. The hub ofthe present invention may be an elastic device. This elasticity may bein either in the FDU or RDU 110. In this regard, an elastic FDU 108a isillustrated by a dashed line in a series connection with main loop 104.It is noted that RDU 110 may be elastic, as shown. Data comes into thehub serially, gets converted from serial to parallel, and then isclocked by a separate clock to retime the data. It should be appreciatedthat the hub of the present invention should be elastic because,depending on the difference between the incoming clock and the localclock, the hub may have to either insert words or delete words. The termelasticity describes absorbing the difference between the clock signals,retiming the data and resetting the jitter to zero. More importantly,what is added is the ability in the hub to insert ordered sets or framesinto the data stream and then also remove the inserted data from thedata stream without interrupting the normal flow of data. For example,an ordered set can be inserted onto the loop which then can go through anumber of devices and come back to the hub to then be removed such thatthe inserted ordered set does not continue to circulate. Since a requestis inserted, it can also be established when the request returns to thehub. Therefore, by observing such a request on one lobe using the RDU,it can be determined what is connected on the lobe as well as the lengthof the connection since the delay in return can be timed.

[0082] Referring to FIG. 19, as previously discussed, ALPA mapping usingOPN's allows for locating devices that are quiescent. In other words,locating devices that are not open and are not arbitrating for the loop.For example, if S1 is quiescent, it will not send out ARB's or be openedby another device. Therefore, an ALPA map based on active devices willnot see S1. The proactive approach of the present invention permitssending out queries to any station to elicit a response, whether thestation is active or not, in performing topology mapping. As mentioned,in order to insert and remove these queries, elasticity is providedwithin the hub with the additional benefits of retiming the data andreseting the jitter to zero. For example, in FIG. 3, elastic FDU 108aretimes data and resets jitter between PCC1 and PCC2.

[0083] Attention is now directed to FIG. 20 for purposes of a discussionof hot cascading performed in accordance with the present invention.FIG. 20 illustrates a system manufactured in accordance with the presentinvention and generally indicated by the reference number 400. System400 includes hubs H1 and H2 wherein at least H2 is produced inaccordance with the present invention. Stations S1 and S2 are connectedto H1 while stations S3 and S4 are connected to H2. Initially, it isassumed that the. hubs are not connected such that two loops areoperating separately. Thus, S1 and S2 may be assigned ALPA 2 and ALPA 1,respectively, on H1. At the same time, S3 and S4 may be assigned ALPA 1and ALPA 2 on H2. Cascading itself is the process of connecting the hubsto one another via a connection path “A”. Hot cascading denotes the factthat the separate loops are already active and the addressees (ALPA's)are already assigned on the separate loops present on H1 and H2.However, as is the case here, it should be appreciated that the ALPA'smay be the same for the stations on each loop. That is, both S2 and S3are assigned ALPA 1 and both S1 and S4 are assigned ALPA 2. Therefore,closing connection A can have disastrous results unless specialprecautions are taken. For example, it is desirable to avoid events suchas data intended for ALPA 2 on H2 to be written to ALPA 2 on H1. Asanother example, if S2 with ALPA 1 tries to send a command to ALPA 2 onH1 (i.e., S2), it can be seen that because of the direction of the loopsthe first station having ALPA 2 that this data will encounter is S4 onH2. Thus, it should be assured that such events do not occur as a resultof hot cascading. The present invention provides two methods forperforming hot cascading, as will be described immediately hereinafter.

[0084] Referring to FIG. 21 in conjunction with FIG. 20, a first hotcascading method is generally indicated by the reference number 420. Thebasis of this method is to reset connection A from H2 prior to insertionand, hence, it may be referred to as a “reset connection” method. Method420 begins with step 422 in which H2 listens for valid input on Rx ofits P3. Thereafter, in step 424, LIP F7 is transmitted from Tx of P3 onH2. When the LIP F7 returns to H2 at P3(Rx), it is known that the remoteH1 loop has returned the LIP, is operating properly and, therefore, isin a position to reset. Step 426 is then entered in which the LIP F7continues to be transmitted from P3(Tx) of H2 while listening on P1(Rx)of H2 for the LIP F7 to return. Following return of the LIP F7, in step428, the LIP is released on P3(Tx) of H2 and normal loop data istransmitted therefrom.

[0085] Referring to FIGS. 20 and 22, a second hot cascading method isgenerally indicated by the reference number 440. The basis of the secondmethod is to reset H2 first and, hence, it may be referred to as a“self-reset” method. Method 440 begins with previously described steps422 and 424. Following step 424, step 442 is performed in which LIP F7is transmitted on P2(Tx) of H2 while listening for the LIP F7 at P1(Rx)of H2. As compared with method 420, in this instance, the LIP istransmitted upstream from the new connection (i.e., connection A) so asto reset H2 prior to H1. Thereafter, in step 444, loop data istransmitted on P3(Tx) of H2 with P3(Rx) of H2 connected into the loop.That is, the new connection is allowed in while transmitting the LIP F7.Following step 444, step 446 transmits normal loop data on P2(Tx) of H2.

[0086] Referring to FIG. 2, RDU 110 also utilizes methods for diagnosingsystem failures outside of hub 102. In a first detection feature, theability to detect a CRC (Cyclic Redundancy Code) error is included so asto detect a data frame with a bit error entering the hub. In addition,because the RDU identifies the error to a hub port, the error domain isvisible and the administrator therefore knows which connection toexplore. Therefore, this feature is useful to a system administrator indetermining if stations are introducing errors. In a second detectionfeature, the RDU also captures the source address (ALPA) of the bad dataframe. The ALPA information combined with the port identification allowsfor further narrowing of the source of the error. Isolation of the errormay be accomplished by identifying which ALPAs show errors and which donot. The boundary has a strong possibility of being the problem spot. Ina third detection feature, invalid Fibre Channel Words are identified.This feature is useful in that invalid Fibre Channel Words are anindication of bit errors on a physical link both inside and outside dataframes. An invalid word indication would occur if a bit error occurredbetween the last station and the RDU. This feature is useful if a fiber,transmitter or receiver is intermittent. It should be appreciated thatall of these detection mechanisms can be collected and displayed in apersistent mode to allow capturing and displaying occurrences that arevery low in frequency. A real time display would blink on and off soquickly as to be invisible to the administrator.

[0087] Using the specification to this point and FIGS. 2-22, it isconsidered that one of ordinary skill in the art may readily practicethe present invention in view of the teachings therein. However, forfurther explanatory purposes, the various configurations and methodsdisclosed thus far will be described in more detail in conjunction withFIGS. 23-34. It is noted that the term Wizard refers to a hubmanufactured in accordance with the present invention, while the termsApprentice and Magician refer to management method configurationsoperating in accordance with the present invention. Immediatelyhereinafter, a description will be provided of an embodiment of a PortControl Integrated Circuit (PCC) manufactured in accordance with thepresent invention and suitable for use in PCC embodiments of theinvention described above. Thereafter, documentation will be providedwith regard to management including specific display provisions.

[0088] 1.0 Purpose

[0089] The purpose of this description is to define the electrical,mechanical and environmental requirements for a Fiber Channel FC-AL HubIntegrated Circuit.

[0090] 2.0 Scope

[0091] This description is limited to the definition of the requirementsof the Integrated Circuit specified herein and to no other IntegratedCircuit.

[0092] 3.0 Applicable Documents/References ANSI X3.272 - 199x FibreChannel Arbitrated Loop X3T11/Project 960D/ Interface (FC-AL) Rev. 4.5TR ANSI X3.XXX - 199x Fibre Channel - Methodologies for Jitter Rev. 1.0Draft F Specification draft Proposed X3 Technical Report (Jitter WorkingGroup)

[0093] 4.0 Electrical Requirements TABLE 4.1 Absolute Maximum Ratings(VEEE, VEET, VEEG, VEEP = GND) Symbol Description Min. Typ. Max. UnitComment Vcc Power supply −0.3 4 V voltage VI_T TTL DC input −0.5 5.5 Vvoltage VI_E ECL DC input Vcc − 2 Vcc V voltage II_E ECL input voltage−2 2 V between differential signal IOH_T TTL output current −20 0 mA(High) IOL_T TTL output current 0 20 mA (Low) IO_E ECL output current−30 0 mA Ta Ambient −55 70 C. Under bias temperature Tstg Storagetemperature −65 150 C.

[0094] TABLE 4.2 Recommended Operating Conditions Symbol DescriptionMin. Typ. Max. Unit Comment Vcc Power supply 3.135 3.3 3.465 V 3.3 V +5% voltage Ta Ambient 0 70 C. temperature

[0095] TABLE 4.3 DC Characteristics (over recommended operatingconditions) Symbol Description Min. Typ. Max. Unit Condition VIH_T InputHIGH voltage (TTL) 2 5.5 V VIL_T Input LOW voltage (TTL) 0 0.8 V IIH_TInput HIGH current (TTL) 20 μA Vin = Vcc IIL_T Input LOW current (TTL)−400 μA Vin = 0 VOH_T Output HIGH voltage (TTL) 2.2 Vcc V IOH = −0.4 mAVOL_T Output LOW voltage (TTL) 0.5 V IOL = 2 mA VIH_E Input HIGH voltage(ECL) Vcc − 1.17 Vcc − 0.88 V VIL_E Input LOW voltage (ECL) Vcc − 1.81Vcc − 1.48 V VIS_E Differential input voltage 200 1000 mV AC coupledswing (ECL) VOH_E Output HIGH voltage (ECL) Vcc − 1.05 Vcc − 0.81 V 50ohm to Vcc − 2 V VOL_E Output LOW voltage (ECL) Vcc − 1.81 Vcc − 1.55 V50 ohm to Vcc − 2 V Icc Supply current 123 154 mA Outputs open Pd Powerdissipation 406 534 mW Outputs open

[0096] TABLE 4.4 AC Characteristics (over recommended operatingconditions) See also FIG. 4. Symbol Description Min Typ. Max. UnitConditions Tir_RC Input TTL rise time of REFCLK 4.8 ns 0.8 V to 2.0 VTif_RC Input TTL fall time of REFCLK 4.8 ns 2.0 V to 0.8 V Tor_T OutputTTL rise time 3.5 ns 0.8 V to 2.0 V, CL = 10 pf Tof_T Output TTL falltime 3.5 ns 2.0 V to 0.8 V, CL = 10 pf Tor_E Output ECL rise time 400 ps20% to 80%, CL = 2 pf Tof_E Output ECL fall time 400 ps 20% to 80%, CL =2 pf SDR Serial Data Rate 1062.5 MBd 1.0 UI = 941 ps RC_TOL REFCLKFrequency Tolerance 100 PPM 53.125 MHz REFCLK RC_DC REFCLK Duty CycleTolerance 10 % X TJT Total Jitter Tolerance, pk-pk, 0.7 UI TJT = FDJT +DJT + RJT 10⁻¹² BER X FDJT Frequency Dependent Jitter Tolerance, 0.1 UILPF R/2 = 62 ohm, pk-pk, 10⁻¹² BER C = 0.1 uf, Note 1 X DJTDeterministic Jitter Tolerance, 0.38 UI LPF R/2 = 62 ohm, pk-pk, 10⁻¹²BER C = 0.1 uf, Note 1 X RJT Random Jitter Tolerance, 0.22 UI LPF R/2 =62 ohm, pk-pk, 10⁻¹² BER C = 0.1 uf, Note 1 X DJout Deterministic JitterOutput, pk-pk 0.02 0.07 UI ± K28.5 serial data, 637 KHz HPF, LPF R/2 =62 ohm, C = 0.1 uf X RJout Random Jitter Output, rms 0.010 0.011 UI00110011 serial data, rms 637 KHz HPF, LPF R/2 = 62 ohm, C = 0.1 uf X8CRJout Accumulated Random Jitter Output, rms 0.011 0.0125 UI 00110011serial data, 8 Cascaded ICs (Port_in rms 637 KHz HPF, LPF to Loop_out)R/2 = 62 ohm, C = 0.1 uf X JXFR_P Jitter Transfer Peaking 0.2 dB00110011 Input, LPF K R/2 = 62 ohm, C = 0.1 uf X JXFR_3d Jitter Transfer3 dB Bandwidth 650 850 KHz 00110011 input, LPF B R/2 = 62 ohm, C = 0.1uf X Tbs Bit Sync Time 2500 bit FC IDLE Pattern X Tfa FrequencyAquisition Time 2000 usec LPF C = 0.1 uf X LDR Lock Detect Range −2 +2 %Frequency, Difference Between and Recovered Clock and Refclk X PLL LockOperation Auto Note 2

[0097] TABLE 4.5 Function of LOOP_OUT (see also FIG. 4) LOOP_SELNLOOP_OUT H Recovered Data L LOOP_IN

[0098] TABLE 4.6 Function of DIAG_OUT (see also FIG. 4) DIAG_SELNDIAG_OUT H Recovered Data L DIAG_IN

[0099] TABLE 4.7 Function of PORT_OUT (see also FIG. 4) PORT_SEL0NPORT_SEL1N PORT_OUT H H Low L H Recovered Data H L DIAG_IN L L LOOP_IN

[0100] TABLE 4.8 Function of Recovered Data (see also FIG. 4) PORT_SEL0NPORT_SEL1N CDR_SELN Recovered Data H H H Low L H H — H L H DIAG_IN L L HLOOP_IN H H L PORT_IN L H L PORT_IN H L L PORT_IN L L L PORT_IN

4.9 Selection of Signal (Note: for Selection of Signal see Table 1above)

[0101] 5.0 Mechanical Specifications 5.1 Pin Description (see also FIG.4) Name Pin No. Type Description X REFCLK 1 I_TTL Reference Clock: WhenLKREFN is Low or CDR input frequence Is unlocked, PLL locks to REFCLKLKDT 2 O_TTL PLL Lock Detector: When PLL doesn't lock, it is Low VEET 3PS Ground for TTL I/O: 0 V. DIAG_IN 4 I_ECL (Diff) Serial data output.(See FIG. 1). DIAG_INN 5 VCCE 6 PS Power Supply for ECL I/O: 3.3 V ± 5%LOOP_IN 7 I_ECL (Diff) Serial data input. (See FIG. 1). LOOP_INN 8 VEEG9 PS Ground for internal logic gate: 0 V. PORT_IN 10 I_ECL (Diff) Serialdata input. (See FIG. 1). PORT_INN 11 LKREFN 12 I_TTL Lock to Reference.An active Low input, LKREFN Causes the PLL lock to the REFCLK VEEP 13 PSGround for PLL: 0 V. LPF1 14 EX Connect to external Loop Filter. LPF2 15EX Connect to external Loop Filter. VCCP 16 PS Power supply for PLL: 3.3V ± 5%. PORT_SEL1N 17 I_TTL Selection for PORT_OUT. (See Table 1)PORT_SEL0N 18 VEEE 19 PS Ground for ECL I/O: 0 V. PORT_OUTN 20 0_ECL(Diff) Serial data output. (See FIG. 1). PORT_OUT 21 VCCE 22 PS Powersupply for ECL I/O: 3.3 V ± 5%. LOOP_OUTN 23 O_ECL (Diff) Serial dataoutput. (See FIG. 1). LOOP_OUT 24 VCCG 25 PS Power supply for internallogic gates: 3.3 V ± 5%. DIAG_INN 26 I_ECL (Diff) Serial data input.(See FIG. 1). DIAG_IN 27 LOOP-SELN 28 I_TTL Selection for LOOP_OUT. (SeeTable 1). DIAG_SELN 29 I_TTL Selection for DIAG_OUT. (See Table 1).CDR_SELN 30 I_TTL When Low, PORT_IN is selected for CDR.

[0102] TABLE 5.2 Pin Type Definition Type Definition PS Power supply orground. I_TTL Input TTL O_TTL Output TTL I_ECL Input ECL O_ECL OutputECL EX External circuit node.

[0103] 6. GUI Requirements

[0104] The primary purpose of the GUI is to enable the user to easilyconfigure and manage one or many stacks. This functionality breaks downinto two general categories, multiple stack (device) management andproblem (fault) detection and isolation. The device management isfocused on viewing the status and controlling physical devices and faultmanagement is focused on viewing the current state of a loop and theconnections to it. In managing the stacks there is a natural hierarchy:stacks, mgmt, hubs, ports. In problem detection and isolationinformation for loop states the hierarchy is: loops, mgmt, hubs, ports.The GUI will present these “cuts” or views into the data.

[0105] The overall requirements of the GUI are:

[0106] eGUI must be intuitive, easy to use, and useful

[0107] Help system

[0108] Multiple Stack device management—ability to view ID, status andcontrols for any manageable item

[0109] Site view

[0110] Single stack view

[0111] Mgmt view

[0112] Hub view

[0113] Port view

[0114] Problem detection and isolation—ability to view how stacks andloops are connected and health information

[0115] Site view

[0116] Single loop view

[0117] Mgmt view

[0118] Hub view

[0119] Port view

[0120] Must provide an Ethernet SNMP interface

[0121] Must be localizable

[0122] Must interface with Apprentice

[0123] Must provide event logging

[0124] 6.1 Site View

[0125] This view will present all active Mgmt cards and all loopsassociated with each card which will give the user a one screenpresentation of the health of all managed stacks and their loops. Since,each managed stack must contain at least one management card and onlyone card can be active within a management stack, the highest level viewwill present the active card within each stack and each card presentedin this view will be indicative of the worst state of the correspondingstack of hubs. In the same respect, the loops displayed will bepresented in a way to reflect their current state (active, shouldinvestigate, down). The user needs the ability to display and modifyidentifying information for both stacks and loops.

[0126] The requirements for this view are:

[0127] Display all manageable/monitorable items

[0128] stacks

[0129] loops

[0130] Identification of all manageable stacks by active mgmt card

[0131] IP

[0132] MAC

[0133] domain name

[0134] user supplied name

[0135] Show worst case state (active, should investigate, down) of allmanageable stacks

[0136] Indicate number of hubs in each stack

[0137] Ability to drill-down on any active Mgmt card for moreinformation on the stack

[0138] Show monitorable loops in each stack

[0139] Identification of all monitorable loops

[0140] user supplied name

[0141] Show current state (active, should investigate, down) of allmonitorable loops

[0142] Indicate number of nodes on loop

[0143] Ability to drill-down on any loop for more loop information

[0144] Some future requirements are:

[0145] Indicate primary In-band management links

[0146] NOT just using thickness of connection

[0147] Indicate secondary In-band management links

[0148] Display In-band Magician management stations

[0149] Future devices

[0150] 6.2 Single Stack View

[0151] This view will show all the hubs in a selected stack but will notnecessarily reflect the physical ordering of the hubs. This logicalstack configuration will show any cascaded hubs and their associatedports within the stack. Cascading of the hubs allows multiple hubsaccess to the same loop and within a stack of hubs, it is possible tohave one or more loops configured in the stack. Each port on a hub canbe attached to a node, a loop of nodes such as a JBOD, or an unmanagedhub.

[0152] The requirements for this view are:

[0153] Display manageable hubs in stack selected

[0154] Indicate which hub has the active Mgmt card

[0155] Show worst case state of ports for each displayed hub

[0156] Display identification of each hub

[0157] serial #

[0158] Indicate presence of Mgmt card in any hub, active or slave

[0159] Display identification of all Mgmt cards present

[0160] MAC

[0161] IP

[0162] user supplied name

[0163] Show hub cascades

[0164] Indicate connections outside of managed stack

[0165] If another hub, allow drill-down of stack

[0166] Clouds=other things with >1 ALPA

[0167] 6.3 Loop View

[0168] Within a loop, it is possible to have one or more stacksconfigured in the loop. Each port on a hub can be used to attach anotherhub, cascaded, into a single loop or each hub can be its own isolatedloop or any other combination of hub connections as long as there is nomore than one loop per hub. Each port on a hub can also be attached toan unmanaged device such as a JBOD. This view will show the logicalmanaged loop topology of the selected loop.

[0169] The requirements for this view are:

[0170] Show all manageablelknown? items in loop selected

[0171] hubs

[0172] clouds=JBOD, rest of loop, other things with >1 ALPA

[0173] label unmanaged hub cloud?

[0174] Indicate which hub has the active Mgmt card

[0175] Show worst case state of ports for each displayed hub

[0176] Display identification of each hub

[0177] serial #

[0178] Indicate presence of Mgmt card in any hub, active or slave

[0179] Display identification of all Mgmt cards present

[0180] MAC

[0181] IP

[0182] name

[0183] Display any loop info available

[0184] throughput

[0185] # of link up/link down

[0186] # of ARBs

[0187] registration

[0188] Display node info per port

[0189] ALPA list

[0190] user supplied name

[0191] user supplied WWN

[0192] user supplied device type

[0193] user supplied manufacturer

[0194] user supplied location

[0195] 6.4 MGMT Card View

[0196] This view should give all pertinent info for a selectedmanagement card and provide mechanisms to modify the configuration ofthe selected Mgmt card.

[0197] The requirements for this view are:

[0198] Display Mgmt card identification information

[0199] MAC

[0200] IP

[0201] HW revision

[0202] FW revision

[0203] Indicate state of Mgmt card

[0204] Allow user to force this Mgmt card to be active

[0205] 6.5 HUB View

[0206] This view will provide status and control information about eachhub in a managed stack or loop and will provide mechanisms to modify theconfiguration of each hub.

[0207] The requirements for this view are:

[0208] Display manageable hub features intuitively

[0209] Indicate port status of all ports using color

[0210] Show LED states and interpret

[0211] port

[0212] management

[0213] management card present

[0214] management card OK

[0215] management card master

[0216] Ethernet activity

[0217] enclosure monitoring/system

[0218] power supply status

[0219] loop up

[0220] enclosure fault

[0221] uC fault

[0222] Display type of GBIC or none per port

[0223] Display Mgmt card if present and identify

[0224] MAC

[0225] IP

[0226] name

[0227] Display serial # of hub

[0228] Allow multiple port views to be displayed

[0229] Display node info per port

[0230] ALPA list

[0231] user supplied name

[0232] user supplied WWN

[0233] user supplied device type

[0234] user supplied manufacturer

[0235] user supplied location

[0236] 6.6 Port View

[0237] This view will allow the user to access all manageable featuresat the port level.

[0238] The requirements for this view are:

[0239] port control

[0240] enable auto insert/bypass if detect fault - loss of signal, lossof lock or transmitter fault (default)

[0241] OR

[0242] force loop bypass

[0243] force external loopback, will force loop bypass

[0244] OR

[0245] force insertion on loop

[0246] port status

[0247] port control state

[0248] enable auto insert/bypass

[0249] force bypass

[0250] external loopback

[0251] force insert into loop

[0252] port module ID copper/fiber(SW,LW) 3 bit GBIC spec id. TABLE6.6-1 Bits 2:0 Definition 111 No Module Present 110 Copper Module, DB-9Connector 101 Copper Module, HSSDC Connector 100 Long-wave Laser 011Serial Interface Protocol 010 Short-wave Laser 001 To Be Defined 000Gigabit Ethernet

[0253] TABLE 6.6-2 Logic Inputs GBIC Mod_(—) TX_(—) Rx_(—) StatusLink_FIt Pres Fault signal Green Amber Description F X X OFF OFF Modulenot inserted T T X OFF ON Faulty Module T F F ON ON Module OK; Missingor Corrupt Data T F T ON OFF Normal Operation

[0254] 7. GUI Design

[0255] The goal of the GUI is to present this functionality in anintuitive and user-friendly package. The primary techniques that will beemployed in accomplishing this goal are:

[0256] a hierarchical presentation with drill-down capabilities startingwith the stack manager at the highest level and drilling down to theindividual port level

[0257] logical topologies using icons that are easily identifiable

[0258] color coding to indicate health for quick problem detection andisolation

[0259] gray=unused

[0260] green=everything is functional

[0261] yellow=needs attention (should be investigated)

[0262] red=failure

[0263] user labeling of all devices

[0264] readily available “how-to use this window” information

[0265] a consistent window interface

[0266] flyover with high-level info on item

[0267] single click=more detailed info on item

[0268] double click=drill-down if available

[0269] a “How to use this window” button

[0270] a “Text/GUI” display toggle button

[0271] comprehensive Help system

[0272] cursor indication of selectable items

[0273] The major design divisions in the application are as follows:

[0274] Views

[0275] Data Objects

[0276] Data Acquirement

[0277] Health Determination

[0278] Management API

[0279] Mgmt API/SNMP mapping wrappers

[0280] SNMP Interface

[0281] Internationalization/Localizability

[0282] Event Log

[0283] 7.1 Views

[0284] There are natural partitions in the information we want topresent. The device management is focused on physical devices and theproblem detection and isolation is focused on the current state of aloop and the connections to it. In presenting the manageable stacksthere is a natural hierarchy: stacks, Mgmt cards, hubs, ports. Inpresenting information for loop states the hierarchy is: loops, Mgmtcards, hubs, ports.

[0285] The proposed hierarchical presentation will drill-down asfollows:

[0286] Site view—all manageable stacks and loops

[0287] Single Stack view

[0288] Mgmt card view

[0289] Back of box view

[0290] Mgmt card view

[0291] Port detail view

[0292] Hardware debug view

[0293] Loop view

[0294] Mgmt card view

[0295] Back of box view

[0296] Mgmt card view

[0297] Port detail view

[0298] Hardware debug view

[0299] The hierarchical presentation will drill-down graphically, asdepicted in FIG. 24 by a diagram that is generally indicated by thereference number 480. Magician will display status and controlinformation about each hub in a managed stack or loop by clicking on ahub from the Stack View (see FIG. 11) or Loop view (see FIG. 25) andwill provide mechanisms to modify the configuration of each hub.

[0300] A polling or change mechanism will be required to keep the viewsin sync with the data. For Apprentice, a simple redraw of objects willbe used. It still needs to be determined the extent of change managementthat should be implemented for Magician.

[0301] 7.1.3 Loop View

[0302] Referring to FIG. 25, a Loop View is generally indicated by thereference number 500. The Loop View will be a tree structure type view.It is intended that the user will be able to “build their own loops” bydragging and dropping hubs into a loop root.

[0303] 7.1.4 Hub View

[0304]FIG. 26 is similar to previously described FIG. 12, however, FIG.26 illustrates another Hub View for Stack 2, Hub 1 generally indicatedby the reference number 520. FIG. 27 illustrates still another Hub Viewfor Stack 2, Hub 3 generally indicated by the reference number 540.

[0305] 7.1.5 Mgmt View

[0306]FIG. 28 illustrates a management view generally indicated by thereference number 560.

[0307] 7.1.7 Hardware Debug

[0308]FIG. 29 illustrates a first hardware debug view which is generallyindicated by the reference number 580. In this view, a “Ports” tab 582has been selected.

[0309]FIG. 30 illustrates hardware debug view 580 with a “Hub” tab 584selected.

[0310]FIG. 31 illustrates hardware debug view 580 with a “Loop” tab 586selected.

[0311]FIG. 32 illustrates hardware debug view 580 with a “Stack” tab 586selected.

[0312]FIG. 33 illustrates hardware debug view 580 with an “Agent” tab588 selected.

[0313] It is noted that the “Detect” tab in FIGS. 29-33 has beenreplaced by a “Sweep” tab having the same functionality. Selection ofthis sweep tab brings up Hub Sweep View 260 of FIG. 14, described above.

[0314] 7.2 Data Objects

[0315] There is also a natural hierarchy of objects in the system wewill be handling. The primary objects identified are:

[0316] lobes: loop nodes, hubs, clouds

[0317] ports

[0318] mgmt cards

[0319] hubs

[0320] stacks active mgmt cards

[0321] loops

[0322] site

[0323] Referring to FIG. 34, a data object composition chart isgenerally indicated by the reference number 600. Each object identifiedhas state and control information associated with it. The stateinformation maps into Visual Basic properties and the controls map intoVisual Basic methods as follows:

[0324] Cloud

[0325] Properties[val Types]

[0326] ALPAs

[0327] Graphic

[0328] Node

[0329] Properties[val Types]

[0330] Name

[0331] WWW

[0332] Location

[0333] DeviceType

[0334] Manufacturer

[0335] Graphic

[0336] Lobe

[0337] Properties[val Types]

[0338] Length

[0339] Type [none, unknown, node, hub]

[0340] ID

[0341] ConnectObject

[0342] Port

[0343] Properties[val Types]

[0344] ControlState[auto, bypass, extloopback, insert]

[0345] BeaconState [Boolean]

[0346] TransmitterState [Boolean]

[0347] ModuleID [GbEther, TBD, LaserSW, Serial, LaserLW, CopperHSSDC,CopperD9, NoModule]

[0348] GBICLED [Boolean]

[0349] FaultLED [On, Off, Blink]

[0350] State [inserted, bypassed, TxFault]

[0351] PllLock[True, False]

[0352] LobeObject

[0353] Utilization

[0354] FailoverPort

[0355] TimesInserted

[0356] Health

[0357] DeviceID

[0358] Graphic

[0359] Methods(args)

[0360] Beacon (Boolean)

[0361] Control (Auto, Bypass, Loopback, Insert)

[0362] Transmitter (Boolean)

[0363] FailoverPortSet

[0364] UpdateInfo

[0365] GetHealth

[0366] SetVars(deviceID, vars, vals)

[0367] RecvVars(deviceID, vars, vals)

[0368] Class_Initialize

[0369] Mgmt

[0370] Properties[val Types]

[0371] State [active, passive, maintenance, unknown]

[0372] FailoverPriority[0 . . . 7]

[0373] MAC

[0374] IP

[0375] SelftestOK [Boolean]

[0376] HardwareVersion

[0377] FirmwareVersion

[0378] LanActivity [Boolean]

[0379] EventLog

[0380] Password

[0381] SyslogHost

[0382] Name

[0383] Health

[0384] DeviceID

[0385] Graphic

[0386] Methods(args)

[0387] FailoverPrioritySet

[0388] PasswordSet

[0389] IpSet

[0390] ForceActive

[0391] EventFilter

[0392] SyslogHostSet

[0393] Reset

[0394] UpdateInfo

[0395] GetHealth

[0396] SetVars(deviceID, vars, vals)

[0397] RecvVars(deviceID, vars, vals)

[0398] Class_Initialize

[0399] Hub

[0400] Properties[val Types]

[0401] FanFault [Boolean]

[0402] TempFault [Boolean]

[0403] PowerFault [Boolean]

[0404] uCFault [Boolean]

[0405] SerialNumber

[0406] Family

[0407] HWType

[0408] NumPorts

[0409] FWVersion

[0410] ManagementPresent [Boolean]

[0411] DiagPort

[0412] PortsObject

[0413] MgmtObject

[0414] LoopObject

[0415] Health

[0416] DeviceID

[0417] Graphic

[0418] Methods(args)

[0419] DiagnosPort

[0420] Reset(I2C, ports)

[0421] UpdateInfo

[0422] GetHealth

[0423] SetVars(deviceID, vars, vals)

[0424] RecvVars(deviceID, vars, vals)

[0425] Class_Initialize

[0426] Loop

[0427] Properties[val Types]

[0428] ID

[0429] State [initializing, open-init, loop up, loop active]

[0430] ALPAs

[0431] UpTime

[0432] TimesReset

[0433] Utilization

[0434] HubsObject

[0435] Health

[0436] DeviceID

[0437] Graphic

[0438] Methods(args)

[0439] Reset

[0440] UpdateInfo

[0441] GetHealth

[0442] SetVars(deviceID, vars, vals)

[0443] RecvVars(deviceID, vars, vals)

[0444] Class_Initialize

[0445] Stack

[0446] Properties[val Types]

[0447] ID

[0448] HubsObject

[0449] LoopsObject

[0450] Health

[0451] DeviceID

[0452] Graphic

[0453] Methods(args)

[0454] Reset

[0455] UpdateInfo

[0456] GetHealth

[0457] SetVars(deviceID, vars, vals)

[0458] RecvVars(deviceID, vars, vals)

[0459] Class_Initialize

[0460] Site

[0461] Properties[val Types]

[0462] Evendog

[0463] AgentsObject

[0464] StacksObject

[0465] Icon

[0466] Health

[0467] DeviceID

[0468] Graphic

[0469] Methods(args)

[0470] UpdateInfo

[0471] GetHealth

[0472] SetVars(deviceID, vars, vals)

[0473] RecvVars(deviceID, vars, vals)

[0474] Class_Initialize

[0475] 7.3 Data Acquisition

[0476] A polling mechanism will be employed to obtain current relevantinformation, which will update the information available for eachobject. The attributes of the poll mechanism are:

[0477] Poll Interval

[0478] 1 min=Default

[0479] This should be user adjustable.

[0480] Amount of data acquired:

[0481] Apprentice only requires a simple “poll all” mechanism,

[0482] Magician might need a more intelligent poll using the event logas a back-off mechanism due to too high of IP loading for a completedata poll on every poll interval. The back-off mechanism will be furtherdefined when the event log definition is stable. The preliminaryalgorithm concept is:

[0483]

request active mgmt ID info from all communicating mgmt cards (active orpassive)=

[0484]

request ALL info from active mgmt cards

[0485] active mgmt=stack

[0486]

poll event logs from all active mgmt cards

[0487]

if change in event log

[0488] get pertinent data

[0489] Another option for minimizing the impact of the poll mechanism isto break requests into chunks instead of requesting all data at once.

[0490] Type of poll

[0491] Apprentice will have a blocking poll

[0492] Magician will have an asynchronous poll provided by the PowerTCPSNMP package

[0493] The functionality will be implemented by using Timer objects. Theability to refresh object information will be provided consistently andgenerically by each object having its own UpdateInfo method.

[0494] 7.4 Health Determination

[0495] Here is the color coding map to indicate health for problemdetection and isolation

[0496] gray=Unused

[0497] green =everything is Functional

[0498] yellow =needs Attention (should be investigated)

[0499] red =Failure

[0500] Each of the following objects will have a health indicator thatwill have an affect on the next level object above it.

[0501] ports

[0502] Unused

[0503] Default

[0504] Functional

[0505] GBICLED=on & FaultLED=off

[0506] Attention

[0507] ControlState !=auto

[0508] State=bypassed

[0509] Failure

[0510] ModuleID !=NoModule & GBICLED=off

[0511] TransmitterState=off

[0512] FaultLED=on

[0513] ControlState=insert & State !=inserted

[0514] mgmt (must be present)

[0515] Unused

[0516] State=passive

[0517] Functional

[0518] State=active & SelftestOK=true & LanActivity=true

[0519] Attention

[0520] State=maintenance

[0521] State !=active & LanActivity=false

[0522] Failure

[0523] State=unknown

[0524] SelftestOK=false

[0525] State=active & LanActivity=false

[0526] hubs

[0527] Unused

[0528] Never

[0529] Functional

[0530] Default

[0531] Attention

[0532] mgmt.health =attention|ports.health=attention

[0533] Failure

[0534] mgmt.health=failure|port.health=failure

[0535] FanFault=true

[0536] TempFault=true

[0537] PowerFault=true

[0538] uCFault=true

[0539] loops

[0540] Unused

[0541] Never

[0542] Functional

[0543] Attention

[0544] Failure

[0545] State !=loopUpiloopActive

[0546] stacks

[0547] Unused

[0548] Never

[0549] Functional

[0550] Default

[0551] Attention

[0552] hubs.health=attention

[0553] Failure

[0554] hubs.health=failure

[0555] site

[0556] Unused

[0557] Never

[0558] Functional

[0559] Default

[0560] Attention

[0561] hubs.health=attention|loops.health=attention

[0562] Failure

[0563] hubs.health=failure|loops.health=failure

[0564] This functionality will be consistently and genericallyimplemented by each object having its own GetHealth method.

[0565] One skilled in the art may devise many alternative configurationsfor the systems and methods disclosed herein. Therefore, it should beunderstood that the present invention may be embodied in many otherspecific forms without departing from the spirit or scope of theinvention and that the present examples and methods are to be consideredas illustrative and not restrictive, and the invention is not to belimited to the details given herein, but may be modified within thescope of the appended claims.

1-71 (canceled)
 72. In a Fibre channel system configured forinterconnection of a plurality of stations using a loop as part of adigital system such that digital data flows including ordered sets flowsbetween the stations on the loop based on operational status of thesystem, said stations being interconnected by a hub which partiallydefines said loop, a management arrangement comprising: a) monitoringmeans forming one part of said hub for non-invasively monitoring aplurality of points distributed on said loop between pairs of saidstations that are adjacent to one another with respect to said loop forthe presence at said points of one of a number of predetermined types ofordered sets, which predetermined ordered set types are indicative ofthe operational status of the stations and of the hub; and b) analysismeans forming another part of said hub for establishing at least onestatus indication based on the presence of said predetermined orderedset types at one or more of said points.
 73. The management arrangementaccording to claim 72 wherein said status indication is selected from anarray of loop states ranging from non-operational to fully operationaland said management arrangement includes control means for responding tosaid status indication in a way which alters the overall configurationof the loop to move the operational status of the system more towardfully operational when the status indication is within a predeterminedrange from non-operational in said array of loop states.
 74. Themanagement arrangement according to claim 72 wherein said statusindication is an overall health indication of the condition of said loopbased upon the predetermined ordered set type that is present at each ofsaid points.
 75. The management arrangement according to claim 72wherein the status indication is selected from a group of loop statesincluding INOPERATIVE, INITIALIZING, OPEN-INIT, UP and UP+FRAME.
 76. Themanagement arrangement according to claim 75 including display meanswherein said loop is represented visually in at least one view as anicon on said display means and wherein said icon includes one of anumber of different colors which denote said status indication.
 77. Themanagement arrangement according to claim 76 wherein each station isphysically connected to one of a number of ports, respectively, on saidhub and wherein said analysis means is configured for generatingadditional status indications such that each port has an associatedadditional status indication and said display means is furtherconfigured such that selection of said icon leads to a hub view which isphysically representative of said hub including said ports and saiddisplay means uses said different colors in association with said portsin a way which indicates the additional status indication associatedwith each port.
 78. The management arrangement according to claim 77wherein selection of one of said ports as represented on said displaymeans leads to an additional view on the display means which includesspecific information related to the selected port and to any stationconnected with the selected port.
 79. The management arrangementaccording to claim 78 including control means forming part of said huband having a series of user selectable port control modes such that anyport may be placed in one of the control modes and wherein said specificinformation includes an indication of the port control mode currentlyselected for the selected port.
 80. The management arrangement accordingto claim 79 wherein said stations are selectively connectable with saidloop using said port control modes and wherein said port control modesinclude an automatic mode in which each station is connected to the loopbased on certain criteria.
 81. The management arrangement according toclaim 79 wherein said stations are selectively connectable with saidloop using said port control modes and wherein said port control modesinclude a forced bypass mode in which any station inserted into any portin forced bypass mode is disconnected from the loop.
 82. The managementarrangement according to claim 79 wherein said stations are selectivelyconnectable with said loop using said port control modes and whereinsaid port control modes include a loop-back mode such that digital datatransmitted from a particular station connected to a port in loop-backmode is returned to that particular station without being transmitted toother stations on the loop.
 83. The management arrangement according toclaim 79 wherein said stations are selectively connectable with saidloop using said port control modes and wherein said port control modesinclude a forced insert mode such that a particular station connected toa port in forced insert mode is always connected to the loop.
 84. Themanagement arrangement according to claim 79 wherein each station isconnected to a respective one of the ports using a gigabit interfaceconverter (GBIC) inserted into the port, each GBIC being selected fromone of a number of possible GBIC types and each GBIC including readableinformation identifying its type out of the number of possible GBICtypes and wherein the management arrangement includes means for readingthe readable information from the GBIC and for providing said readableinformation as part of said specific information.
 85. The managementarrangement according to claim 77 including control means forming partof said hub and configured such that any port may be beaconed in apredetermined way and wherein selection of one of said ports asrepresented on said display means leads to a port view on the displaymeans which includes means for causing the selected port to be beaconed.86. The management arrangement according to claim 85 wherein saidadditional view includes a beacon port selection box for causing theselected port to be beaconed.
 87. The management arrangement accordingto claim 85 wherein said beaconing of the selected port is visible inthe hub view in a way which directs a viewer's attention to the selectedport.
 88. The management arrangement according to claim 85 wherein theselected port is beaconed in said predetermined way using beaconingmeans located physically adjacent to the selected port on said hub. 89.The management arrangement according to claim 85 wherein said beaconingmeans includes a light emitting arrangement adjacent to the selectedport on said hub which flashes at a selected interval when the selectedport is beaconed.
 90. The management arrangement according to claim 72further comprising: c) display means for simultaneously displaying thepredetermined ordered set type which is present at each one of saidpoints so as to enable an operator of the system to make determinationsas to an individual status of each one of the stations.
 91. Themanagement arrangement according to claim 90 wherein the predeterminedordered set types include LIP, LIP F7, LIP F8, OPN, ARB, SOF, USR andIDLE.
 92. In a Fibre channel system configured for interconnection of aplurality of stations using a loop as part of a digital system such thatdigital data including ordered sets flows between the stations on theloop based on operational status of the system, said stations beinginterconnected by a hub which partially defines said loop, a methodcomprising the steps of: a) non-invasively monitoring a plurality ofpoints distributed on said loop between pairs of said stations that areadjacent to one another with respect to said loop for the presence ofone of a number of predetermined types of ordered sets, whichpredetermined ordered set types are indicative of the operational statusof the stations and of the loop; and b) establishing at least one statusindication based on the presence of said predetermined ordered set typesat one or more of said points.
 93. The method according to claim 92wherein said status indication is selected from an array of loop statesranging from non-operational to fully operational and said methodincludes the step of responding to said status indication in a way whichalters the overall configuration of the loop to move the operationalstatus of the system more toward fully operational when the statusindication is within a predetermined range from non-operational in saidarray of loop states.
 94. The method according to claim 92 wherein saidstatus indication is an overall health indication of the condition ofsaid loop based upon the predetermined ordered set type that is presentat each of said points.
 95. The method according to claim 94 wherein thestatus indication is selected from a group of loop states includingINOPERATIVE, INITIALIZING, OPEN−INIT, UP and UP+FRAME.
 96. The methodaccording to claim 92 including the step of visually displaying saidloop as an icon including one of a number of different colors whichdenote said status indication.
 97. The method according to claim 92including the step of simultaneously displaying the predeterminedordered set type which is present at each one of said points so as toenable an operator of the system to make determinations as to anindividual status of each one of the stations. 98-107 (canceled)
 108. Ina Fibre Channel system configured for interconnection of a plurality ofstations as part of a digital system using a main loop such that digitaldata flows between the stations on the main loop through a hub, said hubbeing configured for interconnection of said stations using a series ofports interfaced with said main loop such that one or more stations areconnected to each port to form a lobe of the main loop, a method ofverifying the integrity of a selected one of said lobes including thestation or stations in the selected lobe, said method comprising thesteps of: a) configuring said hub for entering a lobe test mode suchthat any digital data transmitted to the hub from the station orstations on the selected lobe in the lobe test mode is returned to theselected lobe; b) placing the selected lobe into the lobe test modewhile digital data present on the main loop continues to flow thereon;and c) thereafter, in the hub, listening on the selected lobe for apredetermined initialization sequence on the selected lobe withoutaffecting digital data flowing on the main loop.
 109. The methodaccording to claim 108 further comprising the step of: d) providing anindication as to the integrity of the selected lobe based upon detectionof the predetermined initialization sequence on the selected lobe. 110.The method according to claim 109 wherein the selected initializationsequence is detected by the sequence of ordered sets including LIP, ARB,CLS and SOF. 111-126 (canceled)